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Shareholder Report
 6 Months Ended
Mar. 31, 2025
USD ($)
Holding
Shareholder Report [Line Items]  
Document Type N-CSRS
Amendment Flag false
Registrant Name Janus Investment Fund
Entity Central Index Key 0000277751
Entity Investment Company Type N-1A
Document Period End Date Mar. 31, 2025
C000077650 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Balanced Fund
Class Name Class A Shares
Trading Symbol JDBAX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Balanced Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Balanced Fund
(Class A Shares/JDBAX)		 $44 0.89%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 44
Expense Ratio, Percent 0.89% [1]
Net Assets $ 25,173,000,000
Holdings Count | Holding 822
Investment Company Portfolio Turnover 32.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $25,173M
Number of portfolio holdings 822
Portfolio turnover rate 32%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 4.9
NVIDIA Corp 4.5
Apple Inc 3.3
Amazon.com Inc 2.9
Alphabet Inc - Class C 2.7
Asset Allocation (% of net assets)
Common Stocks 60.2
Corporate Bonds 14.4
Asset-Backed/Commercial Mortgage-Backed Securities 12.3
Mortgage-Backed Securities 8.8
Investment Companies 2.3
United States Treasury Notes/Bonds 2.1
Bank Loans and Mezzanine Loans 0.7
Investments Purchased with Cash Collateral from Securities Lending 0.0
Other (0.8)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 4.9
NVIDIA Corp 4.5
Apple Inc 3.3
Amazon.com Inc 2.9
Alphabet Inc - Class C 2.7
C000077651 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Balanced Fund
Class Name Class C Shares
Trading Symbol JABCX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Balanced Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Balanced Fund
(Class C Shares/JABCX)		 $80 1.62%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 80
Expense Ratio, Percent 1.62% [2]
Net Assets $ 25,173,000,000
Holdings Count | Holding 822
Investment Company Portfolio Turnover 32.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $25,173M
Number of portfolio holdings 822
Portfolio turnover rate 32%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 4.9
NVIDIA Corp 4.5
Apple Inc 3.3
Amazon.com Inc 2.9
Alphabet Inc - Class C 2.7
Asset Allocation (% of net assets)
Common Stocks 60.2
Corporate Bonds 14.4
Asset-Backed/Commercial Mortgage-Backed Securities 12.3
Mortgage-Backed Securities 8.8
Investment Companies 2.3
United States Treasury Notes/Bonds 2.1
Bank Loans and Mezzanine Loans 0.7
Investments Purchased with Cash Collateral from Securities Lending 0.0
Other (0.8)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 4.9
NVIDIA Corp 4.5
Apple Inc 3.3
Amazon.com Inc 2.9
Alphabet Inc - Class C 2.7
C000083512 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Balanced Fund
Class Name Class D Shares
Trading Symbol JANBX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Balanced Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/reports. You can also request this information by contacting us at 1-800-525-3713.
Additional Information Phone Number 1-800-525-3713
Additional Information Website janushenderson.com/reports
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Balanced Fund
(Class D Shares/JANBX)		 $34 0.69%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 34
Expense Ratio, Percent 0.69% [3]
Net Assets $ 25,173,000,000
Holdings Count | Holding 822
Investment Company Portfolio Turnover 32.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $25,173M
Number of portfolio holdings 822
Portfolio turnover rate 32%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 4.9
NVIDIA Corp 4.5
Apple Inc 3.3
Amazon.com Inc 2.9
Alphabet Inc - Class C 2.7
Asset Allocation (% of net assets)
Common Stocks 60.2
Corporate Bonds 14.4
Asset-Backed/Commercial Mortgage-Backed Securities 12.3
Mortgage-Backed Securities 8.8
Investment Companies 2.3
United States Treasury Notes/Bonds 2.1
Bank Loans and Mezzanine Loans 0.7
Investments Purchased with Cash Collateral from Securities Lending 0.0
Other (0.8)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 4.9
NVIDIA Corp 4.5
Apple Inc 3.3
Amazon.com Inc 2.9
Alphabet Inc - Class C 2.7
C000077652 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Balanced Fund
Class Name Class I Shares
Trading Symbol JBALX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Balanced Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Balanced Fund
(Class I Shares/JBALX)		 $33 0.67%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 33
Expense Ratio, Percent 0.67% [4]
Net Assets $ 25,173,000,000
Holdings Count | Holding 822
Investment Company Portfolio Turnover 32.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $25,173M
Number of portfolio holdings 822
Portfolio turnover rate 32%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 4.9
NVIDIA Corp 4.5
Apple Inc 3.3
Amazon.com Inc 2.9
Alphabet Inc - Class C 2.7
Asset Allocation (% of net assets)
Common Stocks 60.2
Corporate Bonds 14.4
Asset-Backed/Commercial Mortgage-Backed Securities 12.3
Mortgage-Backed Securities 8.8
Investment Companies 2.3
United States Treasury Notes/Bonds 2.1
Bank Loans and Mezzanine Loans 0.7
Investments Purchased with Cash Collateral from Securities Lending 0.0
Other (0.8)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 4.9
NVIDIA Corp 4.5
Apple Inc 3.3
Amazon.com Inc 2.9
Alphabet Inc - Class C 2.7
C000114869 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Balanced Fund
Class Name Class N Shares
Trading Symbol JABNX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Balanced Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Balanced Fund
(Class N Shares/JABNX)		 $28 0.57%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 28
Expense Ratio, Percent 0.57% [5]
Net Assets $ 25,173,000,000
Holdings Count | Holding 822
Investment Company Portfolio Turnover 32.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $25,173M
Number of portfolio holdings 822
Portfolio turnover rate 32%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 4.9
NVIDIA Corp 4.5
Apple Inc 3.3
Amazon.com Inc 2.9
Alphabet Inc - Class C 2.7
Asset Allocation (% of net assets)
Common Stocks 60.2
Corporate Bonds 14.4
Asset-Backed/Commercial Mortgage-Backed Securities 12.3
Mortgage-Backed Securities 8.8
Investment Companies 2.3
United States Treasury Notes/Bonds 2.1
Bank Loans and Mezzanine Loans 0.7
Investments Purchased with Cash Collateral from Securities Lending 0.0
Other (0.8)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 4.9
NVIDIA Corp 4.5
Apple Inc 3.3
Amazon.com Inc 2.9
Alphabet Inc - Class C 2.7
C000077653 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Balanced Fund
Class Name Class R Shares
Trading Symbol JDBRX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Balanced Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Balanced Fund
(Class R Shares/JDBRX)		 $65 1.32%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 65
Expense Ratio, Percent 1.32% [6]
Net Assets $ 25,173,000,000
Holdings Count | Holding 822
Investment Company Portfolio Turnover 32.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $25,173M
Number of portfolio holdings 822
Portfolio turnover rate 32%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 4.9
NVIDIA Corp 4.5
Apple Inc 3.3
Amazon.com Inc 2.9
Alphabet Inc - Class C 2.7
Asset Allocation (% of net assets)
Common Stocks 60.2
Corporate Bonds 14.4
Asset-Backed/Commercial Mortgage-Backed Securities 12.3
Mortgage-Backed Securities 8.8
Investment Companies 2.3
United States Treasury Notes/Bonds 2.1
Bank Loans and Mezzanine Loans 0.7
Investments Purchased with Cash Collateral from Securities Lending 0.0
Other (0.8)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 4.9
NVIDIA Corp 4.5
Apple Inc 3.3
Amazon.com Inc 2.9
Alphabet Inc - Class C 2.7
C000077654 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Balanced Fund
Class Name Class S Shares
Trading Symbol JABRX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Balanced Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Balanced Fund
(Class S Shares/JABRX)		 $53 1.07%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 53
Expense Ratio, Percent 1.07% [7]
Net Assets $ 25,173,000,000
Holdings Count | Holding 822
Investment Company Portfolio Turnover 32.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $25,173M
Number of portfolio holdings 822
Portfolio turnover rate 32%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 4.9
NVIDIA Corp 4.5
Apple Inc 3.3
Amazon.com Inc 2.9
Alphabet Inc - Class C 2.7
Asset Allocation (% of net assets)
Common Stocks 60.2
Corporate Bonds 14.4
Asset-Backed/Commercial Mortgage-Backed Securities 12.3
Mortgage-Backed Securities 8.8
Investment Companies 2.3
United States Treasury Notes/Bonds 2.1
Bank Loans and Mezzanine Loans 0.7
Investments Purchased with Cash Collateral from Securities Lending 0.0
Other (0.8)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 4.9
NVIDIA Corp 4.5
Apple Inc 3.3
Amazon.com Inc 2.9
Alphabet Inc - Class C 2.7
C000028918 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Balanced Fund
Class Name Class T Shares
Trading Symbol JABAX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Balanced Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Balanced Fund
(Class T Shares/JABAX)		 $40 0.81%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 40
Expense Ratio, Percent 0.81% [8]
Net Assets $ 25,173,000,000
Holdings Count | Holding 822
Investment Company Portfolio Turnover 32.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $25,173M
Number of portfolio holdings 822
Portfolio turnover rate 32%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 4.9
NVIDIA Corp 4.5
Apple Inc 3.3
Amazon.com Inc 2.9
Alphabet Inc - Class C 2.7
Asset Allocation (% of net assets)
Common Stocks 60.2
Corporate Bonds 14.4
Asset-Backed/Commercial Mortgage-Backed Securities 12.3
Mortgage-Backed Securities 8.8
Investment Companies 2.3
United States Treasury Notes/Bonds 2.1
Bank Loans and Mezzanine Loans 0.7
Investments Purchased with Cash Collateral from Securities Lending 0.0
Other (0.8)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 4.9
NVIDIA Corp 4.5
Apple Inc 3.3
Amazon.com Inc 2.9
Alphabet Inc - Class C 2.7
C000077655 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Technology and Innovation Fund
Class Name Class A Shares
Trading Symbol JATAX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Technology and Innovation Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Technology and Innovation Fund
(Class A Shares/JATAX)		 $49 1.03%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 49
Expense Ratio, Percent 1.03% [9]
Net Assets $ 6,413,000,000
Holdings Count | Holding 72
Investment Company Portfolio Turnover 30.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $6,413M
Number of portfolio holdings 72
Portfolio turnover rate 30%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
NVIDIA Corp 11.5
Microsoft Corp 10.9
Taiwan Semiconductor Manufacturing Co Ltd 8.2
Apple Inc 6.4
Amazon.com Inc 4.4
Asset Allocation (% of net assets)
Common Stocks 98.2
Private Placements 1.0
Investment Companies 0.9
Investments Purchased with Cash Collateral from Securities Lending 0.1
Warrants 0.0
Other (0.2)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
NVIDIA Corp 11.5
Microsoft Corp 10.9
Taiwan Semiconductor Manufacturing Co Ltd 8.2
Apple Inc 6.4
Amazon.com Inc 4.4
C000077656 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Technology and Innovation Fund
Class Name Class C Shares
Trading Symbol JAGCX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Technology and Innovation Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Technology and Innovation Fund
(Class C Shares/JAGCX)		 $84 1.75%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 84
Expense Ratio, Percent 1.75% [10]
Net Assets $ 6,413,000,000
Holdings Count | Holding 72
Investment Company Portfolio Turnover 30.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $6,413M
Number of portfolio holdings 72
Portfolio turnover rate 30%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
NVIDIA Corp 11.5
Microsoft Corp 10.9
Taiwan Semiconductor Manufacturing Co Ltd 8.2
Apple Inc 6.4
Amazon.com Inc 4.4
Asset Allocation (% of net assets)
Common Stocks 98.2
Private Placements 1.0
Investment Companies 0.9
Investments Purchased with Cash Collateral from Securities Lending 0.1
Warrants 0.0
Other (0.2)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
NVIDIA Corp 11.5
Microsoft Corp 10.9
Taiwan Semiconductor Manufacturing Co Ltd 8.2
Apple Inc 6.4
Amazon.com Inc 4.4
C000083513 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Technology and Innovation Fund
Class Name Class D Shares
Trading Symbol JNGTX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Technology and Innovation Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/reports. You can also request this information by contacting us at 1-800-525-3713.
Additional Information Phone Number 1-800-525-3713
Additional Information Website janushenderson.com/reports
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Technology and Innovation Fund
(Class D Shares/JNGTX)		 $40 0.83%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 40
Expense Ratio, Percent 0.83% [11]
Net Assets $ 6,413,000,000
Holdings Count | Holding 72
Investment Company Portfolio Turnover 30.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $6,413M
Number of portfolio holdings 72
Portfolio turnover rate 30%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
NVIDIA Corp 11.5
Microsoft Corp 10.9
Taiwan Semiconductor Manufacturing Co Ltd 8.2
Apple Inc 6.4
Amazon.com Inc 4.4
Asset Allocation (% of net assets)
Common Stocks 98.2
Private Placements 1.0
Investment Companies 0.9
Investments Purchased with Cash Collateral from Securities Lending 0.1
Warrants 0.0
Other (0.2)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
NVIDIA Corp 11.5
Microsoft Corp 10.9
Taiwan Semiconductor Manufacturing Co Ltd 8.2
Apple Inc 6.4
Amazon.com Inc 4.4
C000077657 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Technology and Innovation Fund
Class Name Class I Shares
Trading Symbol JATIX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Technology and Innovation Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Technology and Innovation Fund
(Class I Shares/JATIX)		 $38 0.80%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 38
Expense Ratio, Percent 0.80% [12]
Net Assets $ 6,413,000,000
Holdings Count | Holding 72
Investment Company Portfolio Turnover 30.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $6,413M
Number of portfolio holdings 72
Portfolio turnover rate 30%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
NVIDIA Corp 11.5
Microsoft Corp 10.9
Taiwan Semiconductor Manufacturing Co Ltd 8.2
Apple Inc 6.4
Amazon.com Inc 4.4
Asset Allocation (% of net assets)
Common Stocks 98.2
Private Placements 1.0
Investment Companies 0.9
Investments Purchased with Cash Collateral from Securities Lending 0.1
Warrants 0.0
Other (0.2)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
NVIDIA Corp 11.5
Microsoft Corp 10.9
Taiwan Semiconductor Manufacturing Co Ltd 8.2
Apple Inc 6.4
Amazon.com Inc 4.4
C000177052 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Technology and Innovation Fund
Class Name Class N Shares
Trading Symbol JATNX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Technology and Innovation Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Technology and Innovation Fund
(Class N Shares/JATNX)		 $34 0.71%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 34
Expense Ratio, Percent 0.71% [13]
Net Assets $ 6,413,000,000
Holdings Count | Holding 72
Investment Company Portfolio Turnover 30.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $6,413M
Number of portfolio holdings 72
Portfolio turnover rate 30%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
NVIDIA Corp 11.5
Microsoft Corp 10.9
Taiwan Semiconductor Manufacturing Co Ltd 8.2
Apple Inc 6.4
Amazon.com Inc 4.4
Asset Allocation (% of net assets)
Common Stocks 98.2
Private Placements 1.0
Investment Companies 0.9
Investments Purchased with Cash Collateral from Securities Lending 0.1
Warrants 0.0
Other (0.2)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
NVIDIA Corp 11.5
Microsoft Corp 10.9
Taiwan Semiconductor Manufacturing Co Ltd 8.2
Apple Inc 6.4
Amazon.com Inc 4.4
C000077658 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Technology and Innovation Fund
Class Name Class S Shares
Trading Symbol JATSX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Technology and Innovation Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Technology and Innovation Fund
(Class S Shares/JATSX)		 $58 1.21%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 58
Expense Ratio, Percent 1.21% [14]
Net Assets $ 6,413,000,000
Holdings Count | Holding 72
Investment Company Portfolio Turnover 30.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $6,413M
Number of portfolio holdings 72
Portfolio turnover rate 30%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
NVIDIA Corp 11.5
Microsoft Corp 10.9
Taiwan Semiconductor Manufacturing Co Ltd 8.2
Apple Inc 6.4
Amazon.com Inc 4.4
Asset Allocation (% of net assets)
Common Stocks 98.2
Private Placements 1.0
Investment Companies 0.9
Investments Purchased with Cash Collateral from Securities Lending 0.1
Warrants 0.0
Other (0.2)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
NVIDIA Corp 11.5
Microsoft Corp 10.9
Taiwan Semiconductor Manufacturing Co Ltd 8.2
Apple Inc 6.4
Amazon.com Inc 4.4
C000028919 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Technology and Innovation Fund
Class Name Class T Shares
Trading Symbol JAGTX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Technology and Innovation Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Technology and Innovation Fund
(Class T Shares/JAGTX)		 $45 0.94%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 45
Expense Ratio, Percent 0.94% [15]
Net Assets $ 6,413,000,000
Holdings Count | Holding 72
Investment Company Portfolio Turnover 30.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $6,413M
Number of portfolio holdings 72
Portfolio turnover rate 30%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
NVIDIA Corp 11.5
Microsoft Corp 10.9
Taiwan Semiconductor Manufacturing Co Ltd 8.2
Apple Inc 6.4
Amazon.com Inc 4.4
Asset Allocation (% of net assets)
Common Stocks 98.2
Private Placements 1.0
Investment Companies 0.9
Investments Purchased with Cash Collateral from Securities Lending 0.1
Warrants 0.0
Other (0.2)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
NVIDIA Corp 11.5
Microsoft Corp 10.9
Taiwan Semiconductor Manufacturing Co Ltd 8.2
Apple Inc 6.4
Amazon.com Inc 4.4
C000077659 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Growth and Income Fund
Class Name Class A Shares
Trading Symbol JDNAX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Growth and Income Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Growth and Income Fund
(Class A Shares/JDNAX)		 $48 0.98%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 48
Expense Ratio, Percent 0.98% [16]
Net Assets $ 6,889,000,000
Holdings Count | Holding 68
Investment Company Portfolio Turnover 28.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $6,889M
Number of portfolio holdings 68
Portfolio turnover rate 28%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 7.8
Apple Inc 5.6
Alphabet Inc - Class C 4.1
Visa Inc 3.7
Broadcom Inc 3.5
Asset Allocation (% of net assets)
Common Stocks 99.7
Investment Companies 0.4
Other (0.1)
Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 7.8
Apple Inc 5.6
Alphabet Inc - Class C 4.1
Visa Inc 3.7
Broadcom Inc 3.5
C000077660 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Growth and Income Fund
Class Name Class C Shares
Trading Symbol JGICX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Growth and Income Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Growth and Income Fund
(Class C Shares/JGICX)		 $79 1.62%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 79
Expense Ratio, Percent 1.62% [17]
Net Assets $ 6,889,000,000
Holdings Count | Holding 68
Investment Company Portfolio Turnover 28.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $6,889M
Number of portfolio holdings 68
Portfolio turnover rate 28%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 7.8
Apple Inc 5.6
Alphabet Inc - Class C 4.1
Visa Inc 3.7
Broadcom Inc 3.5
Asset Allocation (% of net assets)
Common Stocks 99.7
Investment Companies 0.4
Other (0.1)
Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 7.8
Apple Inc 5.6
Alphabet Inc - Class C 4.1
Visa Inc 3.7
Broadcom Inc 3.5
C000083515 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Growth and Income Fund
Class Name Class D Shares
Trading Symbol JNGIX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Growth and Income Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/reports. You can also request this information by contacting us at 1-800-525-3713.
Additional Information Phone Number 1-800-525-3713
Additional Information Website janushenderson.com/reports
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Growth and Income Fund
(Class D Shares/JNGIX)		 $36 0.74%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 36
Expense Ratio, Percent 0.74% [18]
Net Assets $ 6,889,000,000
Holdings Count | Holding 68
Investment Company Portfolio Turnover 28.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $6,889M
Number of portfolio holdings 68
Portfolio turnover rate 28%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 7.8
Apple Inc 5.6
Alphabet Inc - Class C 4.1
Visa Inc 3.7
Broadcom Inc 3.5
Asset Allocation (% of net assets)
Common Stocks 99.7
Investment Companies 0.4
Other (0.1)
Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 7.8
Apple Inc 5.6
Alphabet Inc - Class C 4.1
Visa Inc 3.7
Broadcom Inc 3.5
C000077661 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Growth and Income Fund
Class Name Class I Shares
Trading Symbol JGINX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Growth and Income Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Growth and Income Fund
(Class I Shares/JGINX)		 $35 0.72%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 35
Expense Ratio, Percent 0.72% [19]
Net Assets $ 6,889,000,000
Holdings Count | Holding 68
Investment Company Portfolio Turnover 28.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $6,889M
Number of portfolio holdings 68
Portfolio turnover rate 28%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 7.8
Apple Inc 5.6
Alphabet Inc - Class C 4.1
Visa Inc 3.7
Broadcom Inc 3.5
Asset Allocation (% of net assets)
Common Stocks 99.7
Investment Companies 0.4
Other (0.1)
Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 7.8
Apple Inc 5.6
Alphabet Inc - Class C 4.1
Visa Inc 3.7
Broadcom Inc 3.5
C000114870 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Growth and Income Fund
Class Name Class N Shares
Trading Symbol JDNNX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Growth and Income Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Growth and Income Fund
(Class N Shares/JDNNX)		 $30 0.62%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 30
Expense Ratio, Percent 0.62% [20]
Net Assets $ 6,889,000,000
Holdings Count | Holding 68
Investment Company Portfolio Turnover 28.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $6,889M
Number of portfolio holdings 68
Portfolio turnover rate 28%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 7.8
Apple Inc 5.6
Alphabet Inc - Class C 4.1
Visa Inc 3.7
Broadcom Inc 3.5
Asset Allocation (% of net assets)
Common Stocks 99.7
Investment Companies 0.4
Other (0.1)
Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 7.8
Apple Inc 5.6
Alphabet Inc - Class C 4.1
Visa Inc 3.7
Broadcom Inc 3.5
C000077662 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Growth and Income Fund
Class Name Class R Shares
Trading Symbol JDNRX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Growth and Income Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Growth and Income Fund
(Class R Shares/JDNRX)		 $66 1.36%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 66
Expense Ratio, Percent 1.36% [21]
Net Assets $ 6,889,000,000
Holdings Count | Holding 68
Investment Company Portfolio Turnover 28.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $6,889M
Number of portfolio holdings 68
Portfolio turnover rate 28%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 7.8
Apple Inc 5.6
Alphabet Inc - Class C 4.1
Visa Inc 3.7
Broadcom Inc 3.5
Asset Allocation (% of net assets)
Common Stocks 99.7
Investment Companies 0.4
Other (0.1)
Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 7.8
Apple Inc 5.6
Alphabet Inc - Class C 4.1
Visa Inc 3.7
Broadcom Inc 3.5
C000077663 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Growth and Income Fund
Class Name Class S Shares
Trading Symbol JADGX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Growth and Income Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Growth and Income Fund
(Class S Shares/JADGX)		 $54 1.11%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 54
Expense Ratio, Percent 1.11% [22]
Net Assets $ 6,889,000,000
Holdings Count | Holding 68
Investment Company Portfolio Turnover 28.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $6,889M
Number of portfolio holdings 68
Portfolio turnover rate 28%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 7.8
Apple Inc 5.6
Alphabet Inc - Class C 4.1
Visa Inc 3.7
Broadcom Inc 3.5
Asset Allocation (% of net assets)
Common Stocks 99.7
Investment Companies 0.4
Other (0.1)
Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 7.8
Apple Inc 5.6
Alphabet Inc - Class C 4.1
Visa Inc 3.7
Broadcom Inc 3.5
C000028923 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Growth and Income Fund
Class Name Class T Shares
Trading Symbol JAGIX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Growth and Income Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Growth and Income Fund
(Class T Shares/JAGIX)		 $42 0.85%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 42
Expense Ratio, Percent 0.85% [23]
Net Assets $ 6,889,000,000
Holdings Count | Holding 68
Investment Company Portfolio Turnover 28.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $6,889M
Number of portfolio holdings 68
Portfolio turnover rate 28%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 7.8
Apple Inc 5.6
Alphabet Inc - Class C 4.1
Visa Inc 3.7
Broadcom Inc 3.5
Asset Allocation (% of net assets)
Common Stocks 99.7
Investment Companies 0.4
Other (0.1)
Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 7.8
Apple Inc 5.6
Alphabet Inc - Class C 4.1
Visa Inc 3.7
Broadcom Inc 3.5
C000077669 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Research Fund
Class Name Class A Shares
Trading Symbol JRAAX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Research Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Research Fund
(Class A Shares/JRAAX)		 $48 0.99%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 48
Expense Ratio, Percent 0.99% [24]
Net Assets $ 22,044,000,000
Holdings Count | Holding 81
Investment Company Portfolio Turnover 13.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $22,044M
Number of portfolio holdings 81
Portfolio turnover rate 13%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
NVIDIA Corp 11.4
Microsoft Corp 11.4
Apple Inc 7.4
Amazon.com Inc 6.9
Alphabet Inc - Class C 6.0
Asset Allocation (% of net assets)
Common Stocks 100.1
Investment Companies 0.0
Other (0.1)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
NVIDIA Corp 11.4
Microsoft Corp 11.4
Apple Inc 7.4
Amazon.com Inc 6.9
Alphabet Inc - Class C 6.0
C000077670 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Research Fund
Class Name Class C Shares
Trading Symbol JRACX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Research Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Research Fund
(Class C Shares/JRACX)		 $85 1.75%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 85
Expense Ratio, Percent 1.75% [25]
Net Assets $ 22,044,000,000
Holdings Count | Holding 81
Investment Company Portfolio Turnover 13.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $22,044M
Number of portfolio holdings 81
Portfolio turnover rate 13%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
NVIDIA Corp 11.4
Microsoft Corp 11.4
Apple Inc 7.4
Amazon.com Inc 6.9
Alphabet Inc - Class C 6.0
Asset Allocation (% of net assets)
Common Stocks 100.1
Investment Companies 0.0
Other (0.1)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
NVIDIA Corp 11.4
Microsoft Corp 11.4
Apple Inc 7.4
Amazon.com Inc 6.9
Alphabet Inc - Class C 6.0
C000083517 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Research Fund
Class Name Class D Shares
Trading Symbol JNRFX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Research Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/reports. You can also request this information by contacting us at 1-800-525-3713.
Additional Information Phone Number 1-800-525-3713
Additional Information Website janushenderson.com/reports
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Research Fund
(Class D Shares/JNRFX)		 $38 0.78%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 38
Expense Ratio, Percent 0.78% [26]
Net Assets $ 22,044,000,000
Holdings Count | Holding 81
Investment Company Portfolio Turnover 13.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $22,044M
Number of portfolio holdings 81
Portfolio turnover rate 13%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
NVIDIA Corp 11.4
Microsoft Corp 11.4
Apple Inc 7.4
Amazon.com Inc 6.9
Alphabet Inc - Class C 6.0
Asset Allocation (% of net assets)
Common Stocks 100.1
Investment Companies 0.0
Other (0.1)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
NVIDIA Corp 11.4
Microsoft Corp 11.4
Apple Inc 7.4
Amazon.com Inc 6.9
Alphabet Inc - Class C 6.0
C000077671 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Research Fund
Class Name Class I Shares
Trading Symbol JRAIX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Research Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Research Fund
(Class I Shares/JRAIX)		 $38 0.77%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 38
Expense Ratio, Percent 0.77% [27]
Net Assets $ 22,044,000,000
Holdings Count | Holding 81
Investment Company Portfolio Turnover 13.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $22,044M
Number of portfolio holdings 81
Portfolio turnover rate 13%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
NVIDIA Corp 11.4
Microsoft Corp 11.4
Apple Inc 7.4
Amazon.com Inc 6.9
Alphabet Inc - Class C 6.0
Asset Allocation (% of net assets)
Common Stocks 100.1
Investment Companies 0.0
Other (0.1)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
NVIDIA Corp 11.4
Microsoft Corp 11.4
Apple Inc 7.4
Amazon.com Inc 6.9
Alphabet Inc - Class C 6.0
C000114872 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Research Fund
Class Name Class N Shares
Trading Symbol JRANX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Research Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Research Fund
(Class N Shares/JRANX)		 $33 0.67%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 33
Expense Ratio, Percent 0.67% [28]
Net Assets $ 22,044,000,000
Holdings Count | Holding 81
Investment Company Portfolio Turnover 13.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $22,044M
Number of portfolio holdings 81
Portfolio turnover rate 13%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
NVIDIA Corp 11.4
Microsoft Corp 11.4
Apple Inc 7.4
Amazon.com Inc 6.9
Alphabet Inc - Class C 6.0
Asset Allocation (% of net assets)
Common Stocks 100.1
Investment Companies 0.0
Other (0.1)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
NVIDIA Corp 11.4
Microsoft Corp 11.4
Apple Inc 7.4
Amazon.com Inc 6.9
Alphabet Inc - Class C 6.0
C000177053 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Research Fund
Class Name Class R Shares
Trading Symbol JRARX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Research Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Research Fund
(Class R Shares/JRARX)		 $68 1.39%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 68
Expense Ratio, Percent 1.39% [29]
Net Assets $ 22,044,000,000
Holdings Count | Holding 81
Investment Company Portfolio Turnover 13.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $22,044M
Number of portfolio holdings 81
Portfolio turnover rate 13%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
NVIDIA Corp 11.4
Microsoft Corp 11.4
Apple Inc 7.4
Amazon.com Inc 6.9
Alphabet Inc - Class C 6.0
Asset Allocation (% of net assets)
Common Stocks 100.1
Investment Companies 0.0
Other (0.1)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
NVIDIA Corp 11.4
Microsoft Corp 11.4
Apple Inc 7.4
Amazon.com Inc 6.9
Alphabet Inc - Class C 6.0
C000077672 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Research Fund
Class Name Class S Shares
Trading Symbol JRASX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Research Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Research Fund
(Class S Shares/JRASX)		 $57 1.17%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 57
Expense Ratio, Percent 1.17% [30]
Net Assets $ 22,044,000,000
Holdings Count | Holding 81
Investment Company Portfolio Turnover 13.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $22,044M
Number of portfolio holdings 81
Portfolio turnover rate 13%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
NVIDIA Corp 11.4
Microsoft Corp 11.4
Apple Inc 7.4
Amazon.com Inc 6.9
Alphabet Inc - Class C 6.0
Asset Allocation (% of net assets)
Common Stocks 100.1
Investment Companies 0.0
Other (0.1)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
NVIDIA Corp 11.4
Microsoft Corp 11.4
Apple Inc 7.4
Amazon.com Inc 6.9
Alphabet Inc - Class C 6.0
C000028926 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Research Fund
Class Name Class T Shares
Trading Symbol JAMRX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Research Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Research Fund
(Class T Shares/JAMRX)		 $44 0.90%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 44
Expense Ratio, Percent 0.90% [31]
Net Assets $ 22,044,000,000
Holdings Count | Holding 81
Investment Company Portfolio Turnover 13.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $22,044M
Number of portfolio holdings 81
Portfolio turnover rate 13%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
NVIDIA Corp 11.4
Microsoft Corp 11.4
Apple Inc 7.4
Amazon.com Inc 6.9
Alphabet Inc - Class C 6.0
Asset Allocation (% of net assets)
Common Stocks 100.1
Investment Companies 0.0
Other (0.1)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
NVIDIA Corp 11.4
Microsoft Corp 11.4
Apple Inc 7.4
Amazon.com Inc 6.9
Alphabet Inc - Class C 6.0
C000077678 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Select Fund
Class Name Class A Shares
Trading Symbol JORAX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Select Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Select Fund
(Class A Shares/JORAX)		 $49 1.01%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 49
Expense Ratio, Percent 1.01% [32]
Net Assets $ 2,666,000,000
Holdings Count | Holding 53
Investment Company Portfolio Turnover 16.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $2,666M
Number of portfolio holdings 53
Portfolio turnover rate 16%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 6.4
BAE Systems PLC 4.7
Microsoft Corp 4.6
Arthur J Gallagher & Co 4.3
NVIDIA Corp 3.6
Asset Allocation (% of net assets)
Common Stocks 98.7
Investment Companies 0.7
Preferred Stocks 0.5
Private Placements 0.0
Other 0.1
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 6.4
BAE Systems PLC 4.7
Microsoft Corp 4.6
Arthur J Gallagher & Co 4.3
NVIDIA Corp 3.6
C000077679 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Select Fund
Class Name Class C Shares
Trading Symbol JORCX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Select Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Select Fund
(Class C Shares/JORCX)		 $93 1.91%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 93
Expense Ratio, Percent 1.91% [33]
Net Assets $ 2,666,000,000
Holdings Count | Holding 53
Investment Company Portfolio Turnover 16.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $2,666M
Number of portfolio holdings 53
Portfolio turnover rate 16%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 6.4
BAE Systems PLC 4.7
Microsoft Corp 4.6
Arthur J Gallagher & Co 4.3
NVIDIA Corp 3.6
Asset Allocation (% of net assets)
Common Stocks 98.7
Investment Companies 0.7
Preferred Stocks 0.5
Private Placements 0.0
Other 0.1
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 6.4
BAE Systems PLC 4.7
Microsoft Corp 4.6
Arthur J Gallagher & Co 4.3
NVIDIA Corp 3.6
C000083520 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Select Fund
Class Name Class D Shares
Trading Symbol JANRX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Select Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/reports. You can also request this information by contacting us at 1-800-525-3713.
Additional Information Phone Number 1-800-525-3713
Additional Information Website janushenderson.com/reports
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Select Fund
(Class D Shares/JANRX)		 $39 0.81%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 39
Expense Ratio, Percent 0.81% [34]
Net Assets $ 2,666,000,000
Holdings Count | Holding 53
Investment Company Portfolio Turnover 16.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $2,666M
Number of portfolio holdings 53
Portfolio turnover rate 16%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 6.4
BAE Systems PLC 4.7
Microsoft Corp 4.6
Arthur J Gallagher & Co 4.3
NVIDIA Corp 3.6
Asset Allocation (% of net assets)
Common Stocks 98.7
Investment Companies 0.7
Preferred Stocks 0.5
Private Placements 0.0
Other 0.1
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 6.4
BAE Systems PLC 4.7
Microsoft Corp 4.6
Arthur J Gallagher & Co 4.3
NVIDIA Corp 3.6
C000077680 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Select Fund
Class Name Class I Shares
Trading Symbol JORFX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Select Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Select Fund
(Class I Shares/JORFX)		 $39 0.80%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 39
Expense Ratio, Percent 0.80% [35]
Net Assets $ 2,666,000,000
Holdings Count | Holding 53
Investment Company Portfolio Turnover 16.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $2,666M
Number of portfolio holdings 53
Portfolio turnover rate 16%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 6.4
BAE Systems PLC 4.7
Microsoft Corp 4.6
Arthur J Gallagher & Co 4.3
NVIDIA Corp 3.6
Asset Allocation (% of net assets)
Common Stocks 98.7
Investment Companies 0.7
Preferred Stocks 0.5
Private Placements 0.0
Other 0.1
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 6.4
BAE Systems PLC 4.7
Microsoft Corp 4.6
Arthur J Gallagher & Co 4.3
NVIDIA Corp 3.6
C000114874 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Select Fund
Class Name Class N Shares
Trading Symbol JSLNX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Select Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Select Fund
(Class N Shares/JSLNX)		 $33 0.68%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 33
Expense Ratio, Percent 0.68% [36]
Net Assets $ 2,666,000,000
Holdings Count | Holding 53
Investment Company Portfolio Turnover 16.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $2,666M
Number of portfolio holdings 53
Portfolio turnover rate 16%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 6.4
BAE Systems PLC 4.7
Microsoft Corp 4.6
Arthur J Gallagher & Co 4.3
NVIDIA Corp 3.6
Asset Allocation (% of net assets)
Common Stocks 98.7
Investment Companies 0.7
Preferred Stocks 0.5
Private Placements 0.0
Other 0.1
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 6.4
BAE Systems PLC 4.7
Microsoft Corp 4.6
Arthur J Gallagher & Co 4.3
NVIDIA Corp 3.6
C000077681 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Select Fund
Class Name Class R Shares
Trading Symbol JORRX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Select Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Select Fund
(Class R Shares/JORRX)		 $74 1.53%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 74
Expense Ratio, Percent 1.53% [37]
Net Assets $ 2,666,000,000
Holdings Count | Holding 53
Investment Company Portfolio Turnover 16.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $2,666M
Number of portfolio holdings 53
Portfolio turnover rate 16%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 6.4
BAE Systems PLC 4.7
Microsoft Corp 4.6
Arthur J Gallagher & Co 4.3
NVIDIA Corp 3.6
Asset Allocation (% of net assets)
Common Stocks 98.7
Investment Companies 0.7
Preferred Stocks 0.5
Private Placements 0.0
Other 0.1
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 6.4
BAE Systems PLC 4.7
Microsoft Corp 4.6
Arthur J Gallagher & Co 4.3
NVIDIA Corp 3.6
C000077682 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Select Fund
Class Name Class S Shares
Trading Symbol JORIX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Select Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Select Fund
(Class S Shares/JORIX)		 $63 1.30%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 63
Expense Ratio, Percent 1.30% [38]
Net Assets $ 2,666,000,000
Holdings Count | Holding 53
Investment Company Portfolio Turnover 16.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $2,666M
Number of portfolio holdings 53
Portfolio turnover rate 16%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 6.4
BAE Systems PLC 4.7
Microsoft Corp 4.6
Arthur J Gallagher & Co 4.3
NVIDIA Corp 3.6
Asset Allocation (% of net assets)
Common Stocks 98.7
Investment Companies 0.7
Preferred Stocks 0.5
Private Placements 0.0
Other 0.1
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 6.4
BAE Systems PLC 4.7
Microsoft Corp 4.6
Arthur J Gallagher & Co 4.3
NVIDIA Corp 3.6
C000028933 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Select Fund
Class Name Class T Shares
Trading Symbol JORNX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Select Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Select Fund
(Class T Shares/JORNX)		 $44 0.91%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 44
Expense Ratio, Percent 0.91% [39]
Net Assets $ 2,666,000,000
Holdings Count | Holding 53
Investment Company Portfolio Turnover 16.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $2,666M
Number of portfolio holdings 53
Portfolio turnover rate 16%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 6.4
BAE Systems PLC 4.7
Microsoft Corp 4.6
Arthur J Gallagher & Co 4.3
NVIDIA Corp 3.6
Asset Allocation (% of net assets)
Common Stocks 98.7
Investment Companies 0.7
Preferred Stocks 0.5
Private Placements 0.0
Other 0.1
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 6.4
BAE Systems PLC 4.7
Microsoft Corp 4.6
Arthur J Gallagher & Co 4.3
NVIDIA Corp 3.6
C000077683 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Contrarian Fund
Class Name Class A Shares
Trading Symbol JCNAX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Contrarian Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Contrarian Fund
(Class A Shares/JCNAX)		 $43 0.90%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 43
Expense Ratio, Percent 0.90% [40]
Net Assets $ 4,367,000,000
Holdings Count | Holding 40
Investment Company Portfolio Turnover 32.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $4,367M
Number of portfolio holdings 40
Portfolio turnover rate 32%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Surgery Partners Inc 5.8
Capital One Financial Corp 5.5
Intercontinental Exchange Inc 5.2
Oracle Corp 5.2
Caesars Entertainment Inc 4.5
Asset Allocation (% of net assets)
Common Stocks 97.7
Convertible Corporate Bonds 1.0
Investment Companies 0.9
Investments Purchased with Cash Collateral from Securities Lending 0.3
Other 0.1
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Surgery Partners Inc 5.8
Capital One Financial Corp 5.5
Intercontinental Exchange Inc 5.2
Oracle Corp 5.2
Caesars Entertainment Inc 4.5
C000077684 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Contrarian Fund
Class Name Class C Shares
Trading Symbol JCNCX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Contrarian Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Contrarian Fund
(Class C Shares/JCNCX)		 $74 1.55%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 74
Expense Ratio, Percent 1.55% [41]
Net Assets $ 4,367,000,000
Holdings Count | Holding 40
Investment Company Portfolio Turnover 32.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $4,367M
Number of portfolio holdings 40
Portfolio turnover rate 32%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Surgery Partners Inc 5.8
Capital One Financial Corp 5.5
Intercontinental Exchange Inc 5.2
Oracle Corp 5.2
Caesars Entertainment Inc 4.5
Asset Allocation (% of net assets)
Common Stocks 97.7
Convertible Corporate Bonds 1.0
Investment Companies 0.9
Investments Purchased with Cash Collateral from Securities Lending 0.3
Other 0.1
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Surgery Partners Inc 5.8
Capital One Financial Corp 5.5
Intercontinental Exchange Inc 5.2
Oracle Corp 5.2
Caesars Entertainment Inc 4.5
C000083521 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Contrarian Fund
Class Name Class D Shares
Trading Symbol JACNX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Contrarian Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/reports. You can also request this information by contacting us at 1-800-525-3713.
Additional Information Phone Number 1-800-525-3713
Additional Information Website janushenderson.com/reports
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Contrarian Fund
(Class D Shares/JACNX)		 $31 0.65%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 31
Expense Ratio, Percent 0.65% [42]
Net Assets $ 4,367,000,000
Holdings Count | Holding 40
Investment Company Portfolio Turnover 32.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $4,367M
Number of portfolio holdings 40
Portfolio turnover rate 32%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Surgery Partners Inc 5.8
Capital One Financial Corp 5.5
Intercontinental Exchange Inc 5.2
Oracle Corp 5.2
Caesars Entertainment Inc 4.5
Asset Allocation (% of net assets)
Common Stocks 97.7
Convertible Corporate Bonds 1.0
Investment Companies 0.9
Investments Purchased with Cash Collateral from Securities Lending 0.3
Other 0.1
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Surgery Partners Inc 5.8
Capital One Financial Corp 5.5
Intercontinental Exchange Inc 5.2
Oracle Corp 5.2
Caesars Entertainment Inc 4.5
C000077685 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Contrarian Fund
Class Name Class I Shares
Trading Symbol JCONX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Contrarian Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Contrarian Fund
(Class I Shares/JCONX)		 $30 0.63%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 30
Expense Ratio, Percent 0.63% [43]
Net Assets $ 4,367,000,000
Holdings Count | Holding 40
Investment Company Portfolio Turnover 32.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $4,367M
Number of portfolio holdings 40
Portfolio turnover rate 32%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Surgery Partners Inc 5.8
Capital One Financial Corp 5.5
Intercontinental Exchange Inc 5.2
Oracle Corp 5.2
Caesars Entertainment Inc 4.5
Asset Allocation (% of net assets)
Common Stocks 97.7
Convertible Corporate Bonds 1.0
Investment Companies 0.9
Investments Purchased with Cash Collateral from Securities Lending 0.3
Other 0.1
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Surgery Partners Inc 5.8
Capital One Financial Corp 5.5
Intercontinental Exchange Inc 5.2
Oracle Corp 5.2
Caesars Entertainment Inc 4.5
C000114875 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Contrarian Fund
Class Name Class N Shares
Trading Symbol JCNNX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Contrarian Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Contrarian Fund
(Class N Shares/JCNNX)		 $25 0.53%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 25
Expense Ratio, Percent 0.53% [44]
Net Assets $ 4,367,000,000
Holdings Count | Holding 40
Investment Company Portfolio Turnover 32.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $4,367M
Number of portfolio holdings 40
Portfolio turnover rate 32%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Surgery Partners Inc 5.8
Capital One Financial Corp 5.5
Intercontinental Exchange Inc 5.2
Oracle Corp 5.2
Caesars Entertainment Inc 4.5
Asset Allocation (% of net assets)
Common Stocks 97.7
Convertible Corporate Bonds 1.0
Investment Companies 0.9
Investments Purchased with Cash Collateral from Securities Lending 0.3
Other 0.1
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Surgery Partners Inc 5.8
Capital One Financial Corp 5.5
Intercontinental Exchange Inc 5.2
Oracle Corp 5.2
Caesars Entertainment Inc 4.5
C000077686 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Contrarian Fund
Class Name Class R Shares
Trading Symbol JCNRX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Contrarian Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Contrarian Fund
(Class R Shares/JCNRX)		 $65 1.36%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 65
Expense Ratio, Percent 1.36% [45]
Net Assets $ 4,367,000,000
Holdings Count | Holding 40
Investment Company Portfolio Turnover 32.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $4,367M
Number of portfolio holdings 40
Portfolio turnover rate 32%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Surgery Partners Inc 5.8
Capital One Financial Corp 5.5
Intercontinental Exchange Inc 5.2
Oracle Corp 5.2
Caesars Entertainment Inc 4.5
Asset Allocation (% of net assets)
Common Stocks 97.7
Convertible Corporate Bonds 1.0
Investment Companies 0.9
Investments Purchased with Cash Collateral from Securities Lending 0.3
Other 0.1
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Surgery Partners Inc 5.8
Capital One Financial Corp 5.5
Intercontinental Exchange Inc 5.2
Oracle Corp 5.2
Caesars Entertainment Inc 4.5
C000077687 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Contrarian Fund
Class Name Class S Shares
Trading Symbol JCNIX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Contrarian Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Contrarian Fund
(Class S Shares/JCNIX)		 $53 1.10%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 53
Expense Ratio, Percent 1.10% [46]
Net Assets $ 4,367,000,000
Holdings Count | Holding 40
Investment Company Portfolio Turnover 32.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $4,367M
Number of portfolio holdings 40
Portfolio turnover rate 32%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Surgery Partners Inc 5.8
Capital One Financial Corp 5.5
Intercontinental Exchange Inc 5.2
Oracle Corp 5.2
Caesars Entertainment Inc 4.5
Asset Allocation (% of net assets)
Common Stocks 97.7
Convertible Corporate Bonds 1.0
Investment Companies 0.9
Investments Purchased with Cash Collateral from Securities Lending 0.3
Other 0.1
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Surgery Partners Inc 5.8
Capital One Financial Corp 5.5
Intercontinental Exchange Inc 5.2
Oracle Corp 5.2
Caesars Entertainment Inc 4.5
C000028934 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Contrarian Fund
Class Name Class T Shares
Trading Symbol JSVAX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Contrarian Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Contrarian Fund
(Class T Shares/JSVAX)		 $36 0.76%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 36
Expense Ratio, Percent 0.76% [47]
Net Assets $ 4,367,000,000
Holdings Count | Holding 40
Investment Company Portfolio Turnover 32.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $4,367M
Number of portfolio holdings 40
Portfolio turnover rate 32%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Surgery Partners Inc 5.8
Capital One Financial Corp 5.5
Intercontinental Exchange Inc 5.2
Oracle Corp 5.2
Caesars Entertainment Inc 4.5
Asset Allocation (% of net assets)
Common Stocks 97.7
Convertible Corporate Bonds 1.0
Investment Companies 0.9
Investments Purchased with Cash Collateral from Securities Lending 0.3
Other 0.1
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Surgery Partners Inc 5.8
Capital One Financial Corp 5.5
Intercontinental Exchange Inc 5.2
Oracle Corp 5.2
Caesars Entertainment Inc 4.5
C000077688 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Overseas Fund
Class Name Class A Shares
Trading Symbol JDIAX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Overseas Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Overseas Fund
(Class A Shares/JDIAX)		 $57 1.15%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 57
Expense Ratio, Percent 1.15% [48]
Net Assets $ 3,312,000,000
Holdings Count | Holding 45
Investment Company Portfolio Turnover 12.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $3,312M
Number of portfolio holdings 45
Portfolio turnover rate 12%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 6.4
BAE Systems PLC 5.1
Erste Group Bank AG 4.2
Liberty Media Corp-Liberty Formula One - Series C 3.9
Dai-ichi Life Holdings Inc 3.7
Asset Allocation (% of net assets)
Common Stocks 97.4
Preferred Stocks 1.2
Investment Companies 1.2
Investments Purchased with Cash Collateral from Securities Lending 0.4
Other (0.2)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 6.4
BAE Systems PLC 5.1
Erste Group Bank AG 4.2
Liberty Media Corp-Liberty Formula One - Series C 3.9
Dai-ichi Life Holdings Inc 3.7
C000077689 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Overseas Fund
Class Name Class C Shares
Trading Symbol JIGCX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Overseas Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Overseas Fund
(Class C Shares/JIGCX)		 $93 1.88%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 93
Expense Ratio, Percent 1.88% [49]
Net Assets $ 3,312,000,000
Holdings Count | Holding 45
Investment Company Portfolio Turnover 12.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $3,312M
Number of portfolio holdings 45
Portfolio turnover rate 12%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 6.4
BAE Systems PLC 5.1
Erste Group Bank AG 4.2
Liberty Media Corp-Liberty Formula One - Series C 3.9
Dai-ichi Life Holdings Inc 3.7
Asset Allocation (% of net assets)
Common Stocks 97.4
Preferred Stocks 1.2
Investment Companies 1.2
Investments Purchased with Cash Collateral from Securities Lending 0.4
Other (0.2)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 6.4
BAE Systems PLC 5.1
Erste Group Bank AG 4.2
Liberty Media Corp-Liberty Formula One - Series C 3.9
Dai-ichi Life Holdings Inc 3.7
C000083522 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Overseas Fund
Class Name Class D Shares
Trading Symbol JNOSX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Overseas Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/reports. You can also request this information by contacting us at 1-800-525-3713.
Additional Information Phone Number 1-800-525-3713
Additional Information Website janushenderson.com/reports
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Overseas Fund
(Class D Shares/JNOSX)		 $44 0.88%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 44
Expense Ratio, Percent 0.88% [50]
Net Assets $ 3,312,000,000
Holdings Count | Holding 45
Investment Company Portfolio Turnover 12.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $3,312M
Number of portfolio holdings 45
Portfolio turnover rate 12%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 6.4
BAE Systems PLC 5.1
Erste Group Bank AG 4.2
Liberty Media Corp-Liberty Formula One - Series C 3.9
Dai-ichi Life Holdings Inc 3.7
Asset Allocation (% of net assets)
Common Stocks 97.4
Preferred Stocks 1.2
Investment Companies 1.2
Investments Purchased with Cash Collateral from Securities Lending 0.4
Other (0.2)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 6.4
BAE Systems PLC 5.1
Erste Group Bank AG 4.2
Liberty Media Corp-Liberty Formula One - Series C 3.9
Dai-ichi Life Holdings Inc 3.7
C000077690 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Overseas Fund
Class Name Class I Shares
Trading Symbol JIGFX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Overseas Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Overseas Fund
(Class I Shares/JIGFX)		 $43 0.86%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 43
Expense Ratio, Percent 0.86% [51]
Net Assets $ 3,312,000,000
Holdings Count | Holding 45
Investment Company Portfolio Turnover 12.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $3,312M
Number of portfolio holdings 45
Portfolio turnover rate 12%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 6.4
BAE Systems PLC 5.1
Erste Group Bank AG 4.2
Liberty Media Corp-Liberty Formula One - Series C 3.9
Dai-ichi Life Holdings Inc 3.7
Asset Allocation (% of net assets)
Common Stocks 97.4
Preferred Stocks 1.2
Investment Companies 1.2
Investments Purchased with Cash Collateral from Securities Lending 0.4
Other (0.2)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 6.4
BAE Systems PLC 5.1
Erste Group Bank AG 4.2
Liberty Media Corp-Liberty Formula One - Series C 3.9
Dai-ichi Life Holdings Inc 3.7
C000114876 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Overseas Fund
Class Name Class N Shares
Trading Symbol JDINX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Overseas Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Overseas Fund
(Class N Shares/JDINX)		 $37 0.74%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 37
Expense Ratio, Percent 0.74% [52]
Net Assets $ 3,312,000,000
Holdings Count | Holding 45
Investment Company Portfolio Turnover 12.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $3,312M
Number of portfolio holdings 45
Portfolio turnover rate 12%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 6.4
BAE Systems PLC 5.1
Erste Group Bank AG 4.2
Liberty Media Corp-Liberty Formula One - Series C 3.9
Dai-ichi Life Holdings Inc 3.7
Asset Allocation (% of net assets)
Common Stocks 97.4
Preferred Stocks 1.2
Investment Companies 1.2
Investments Purchased with Cash Collateral from Securities Lending 0.4
Other (0.2)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 6.4
BAE Systems PLC 5.1
Erste Group Bank AG 4.2
Liberty Media Corp-Liberty Formula One - Series C 3.9
Dai-ichi Life Holdings Inc 3.7
C000077691 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Overseas Fund
Class Name Class R Shares
Trading Symbol JDIRX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Overseas Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Overseas Fund
(Class R Shares/JDIRX)		 $74 1.49%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 74
Expense Ratio, Percent 1.49% [53]
Net Assets $ 3,312,000,000
Holdings Count | Holding 45
Investment Company Portfolio Turnover 12.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $3,312M
Number of portfolio holdings 45
Portfolio turnover rate 12%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 6.4
BAE Systems PLC 5.1
Erste Group Bank AG 4.2
Liberty Media Corp-Liberty Formula One - Series C 3.9
Dai-ichi Life Holdings Inc 3.7
Asset Allocation (% of net assets)
Common Stocks 97.4
Preferred Stocks 1.2
Investment Companies 1.2
Investments Purchased with Cash Collateral from Securities Lending 0.4
Other (0.2)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 6.4
BAE Systems PLC 5.1
Erste Group Bank AG 4.2
Liberty Media Corp-Liberty Formula One - Series C 3.9
Dai-ichi Life Holdings Inc 3.7
C000077692 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Overseas Fund
Class Name Class S Shares
Trading Symbol JIGRX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Overseas Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Overseas Fund
(Class S Shares/JIGRX)		 $61 1.24%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 61
Expense Ratio, Percent 1.24% [54]
Net Assets $ 3,312,000,000
Holdings Count | Holding 45
Investment Company Portfolio Turnover 12.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $3,312M
Number of portfolio holdings 45
Portfolio turnover rate 12%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 6.4
BAE Systems PLC 5.1
Erste Group Bank AG 4.2
Liberty Media Corp-Liberty Formula One - Series C 3.9
Dai-ichi Life Holdings Inc 3.7
Asset Allocation (% of net assets)
Common Stocks 97.4
Preferred Stocks 1.2
Investment Companies 1.2
Investments Purchased with Cash Collateral from Securities Lending 0.4
Other (0.2)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 6.4
BAE Systems PLC 5.1
Erste Group Bank AG 4.2
Liberty Media Corp-Liberty Formula One - Series C 3.9
Dai-ichi Life Holdings Inc 3.7
C000028935 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Overseas Fund
Class Name Class T Shares
Trading Symbol JAOSX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Overseas Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Overseas Fund
(Class T Shares/JAOSX)		 $49 0.98%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 49
Expense Ratio, Percent 0.98% [55]
Net Assets $ 3,312,000,000
Holdings Count | Holding 45
Investment Company Portfolio Turnover 12.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $3,312M
Number of portfolio holdings 45
Portfolio turnover rate 12%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 6.4
BAE Systems PLC 5.1
Erste Group Bank AG 4.2
Liberty Media Corp-Liberty Formula One - Series C 3.9
Dai-ichi Life Holdings Inc 3.7
Asset Allocation (% of net assets)
Common Stocks 97.4
Preferred Stocks 1.2
Investment Companies 1.2
Investments Purchased with Cash Collateral from Securities Lending 0.4
Other (0.2)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 6.4
BAE Systems PLC 5.1
Erste Group Bank AG 4.2
Liberty Media Corp-Liberty Formula One - Series C 3.9
Dai-ichi Life Holdings Inc 3.7
C000077722 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Triton Fund
Class Name Class A Shares
Trading Symbol JGMAX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Triton Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Triton Fund
(Class A Shares/JGMAX)		 $54 1.12%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 54
Expense Ratio, Percent 1.12% [56]
Net Assets $ 5,539,000,000
Holdings Count | Holding 126
Investment Company Portfolio Turnover 13.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $5,539M
Number of portfolio holdings 126
Portfolio turnover rate 13%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
SS&C Technologies Holdings Inc 3.0
Teledyne Technologies Inc 2.6
OSI Systems Inc 2.5
Casey's General Stores Inc 1.9
LPL Financial Holdings Inc 1.9
Asset Allocation (% of net assets)
Common Stocks 98.0
Investment Companies 1.9
Investments Purchased with Cash Collateral from Securities Lending 0.9
Private Placements 0.4
OTC Purchased Options – Calls 0.0
Warrants 0.0
Other (1.2)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
SS&C Technologies Holdings Inc 3.0
Teledyne Technologies Inc 2.6
OSI Systems Inc 2.5
Casey's General Stores Inc 1.9
LPL Financial Holdings Inc 1.9
C000077723 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Triton Fund
Class Name Class C Shares
Trading Symbol JGMCX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Triton Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Triton Fund
(Class C Shares/JGMCX)		 $80 1.67%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 80
Expense Ratio, Percent 1.67% [57]
Net Assets $ 5,539,000,000
Holdings Count | Holding 126
Investment Company Portfolio Turnover 13.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $5,539M
Number of portfolio holdings 126
Portfolio turnover rate 13%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
SS&C Technologies Holdings Inc 3.0
Teledyne Technologies Inc 2.6
OSI Systems Inc 2.5
Casey's General Stores Inc 1.9
LPL Financial Holdings Inc 1.9
Asset Allocation (% of net assets)
Common Stocks 98.0
Investment Companies 1.9
Investments Purchased with Cash Collateral from Securities Lending 0.9
Private Placements 0.4
OTC Purchased Options – Calls 0.0
Warrants 0.0
Other (1.2)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
SS&C Technologies Holdings Inc 3.0
Teledyne Technologies Inc 2.6
OSI Systems Inc 2.5
Casey's General Stores Inc 1.9
LPL Financial Holdings Inc 1.9
C000083530 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Triton Fund
Class Name Class D Shares
Trading Symbol JANIX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Triton Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/reports. You can also request this information by contacting us at 1-800-525-3713.
Additional Information Phone Number 1-800-525-3713
Additional Information Website janushenderson.com/reports
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Triton Fund
(Class D Shares/JANIX)		 $38 0.79%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 38
Expense Ratio, Percent 0.79% [58]
Net Assets $ 5,539,000,000
Holdings Count | Holding 126
Investment Company Portfolio Turnover 13.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $5,539M
Number of portfolio holdings 126
Portfolio turnover rate 13%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
SS&C Technologies Holdings Inc 3.0
Teledyne Technologies Inc 2.6
OSI Systems Inc 2.5
Casey's General Stores Inc 1.9
LPL Financial Holdings Inc 1.9
Asset Allocation (% of net assets)
Common Stocks 98.0
Investment Companies 1.9
Investments Purchased with Cash Collateral from Securities Lending 0.9
Private Placements 0.4
OTC Purchased Options – Calls 0.0
Warrants 0.0
Other (1.2)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
SS&C Technologies Holdings Inc 3.0
Teledyne Technologies Inc 2.6
OSI Systems Inc 2.5
Casey's General Stores Inc 1.9
LPL Financial Holdings Inc 1.9
C000077724 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Triton Fund
Class Name Class I Shares
Trading Symbol JSMGX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Triton Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Triton Fund
(Class I Shares/JSMGX)		 $37 0.78%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 37
Expense Ratio, Percent 0.78% [59]
Net Assets $ 5,539,000,000
Holdings Count | Holding 126
Investment Company Portfolio Turnover 13.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $5,539M
Number of portfolio holdings 126
Portfolio turnover rate 13%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
SS&C Technologies Holdings Inc 3.0
Teledyne Technologies Inc 2.6
OSI Systems Inc 2.5
Casey's General Stores Inc 1.9
LPL Financial Holdings Inc 1.9
Asset Allocation (% of net assets)
Common Stocks 98.0
Investment Companies 1.9
Investments Purchased with Cash Collateral from Securities Lending 0.9
Private Placements 0.4
OTC Purchased Options – Calls 0.0
Warrants 0.0
Other (1.2)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
SS&C Technologies Holdings Inc 3.0
Teledyne Technologies Inc 2.6
OSI Systems Inc 2.5
Casey's General Stores Inc 1.9
LPL Financial Holdings Inc 1.9
C000114880 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Triton Fund
Class Name Class N Shares
Trading Symbol JGMNX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Triton Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Triton Fund
(Class N Shares/JGMNX)		 $32 0.67%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 32
Expense Ratio, Percent 0.67% [60]
Net Assets $ 5,539,000,000
Holdings Count | Holding 126
Investment Company Portfolio Turnover 13.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $5,539M
Number of portfolio holdings 126
Portfolio turnover rate 13%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
SS&C Technologies Holdings Inc 3.0
Teledyne Technologies Inc 2.6
OSI Systems Inc 2.5
Casey's General Stores Inc 1.9
LPL Financial Holdings Inc 1.9
Asset Allocation (% of net assets)
Common Stocks 98.0
Investment Companies 1.9
Investments Purchased with Cash Collateral from Securities Lending 0.9
Private Placements 0.4
OTC Purchased Options – Calls 0.0
Warrants 0.0
Other (1.2)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
SS&C Technologies Holdings Inc 3.0
Teledyne Technologies Inc 2.6
OSI Systems Inc 2.5
Casey's General Stores Inc 1.9
LPL Financial Holdings Inc 1.9
C000077725 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Triton Fund
Class Name Class R Shares
Trading Symbol JGMRX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Triton Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Triton Fund
(Class R Shares/JGMRX)		 $67 1.41%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 67
Expense Ratio, Percent 1.41% [61]
Net Assets $ 5,539,000,000
Holdings Count | Holding 126
Investment Company Portfolio Turnover 13.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $5,539M
Number of portfolio holdings 126
Portfolio turnover rate 13%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
SS&C Technologies Holdings Inc 3.0
Teledyne Technologies Inc 2.6
OSI Systems Inc 2.5
Casey's General Stores Inc 1.9
LPL Financial Holdings Inc 1.9
Asset Allocation (% of net assets)
Common Stocks 98.0
Investment Companies 1.9
Investments Purchased with Cash Collateral from Securities Lending 0.9
Private Placements 0.4
OTC Purchased Options – Calls 0.0
Warrants 0.0
Other (1.2)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
SS&C Technologies Holdings Inc 3.0
Teledyne Technologies Inc 2.6
OSI Systems Inc 2.5
Casey's General Stores Inc 1.9
LPL Financial Holdings Inc 1.9
C000077726 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Triton Fund
Class Name Class S Shares
Trading Symbol JGMIX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Triton Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Triton Fund
(Class S Shares/JGMIX)		 $55 1.16%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 55
Expense Ratio, Percent 1.16% [62]
Net Assets $ 5,539,000,000
Holdings Count | Holding 126
Investment Company Portfolio Turnover 13.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $5,539M
Number of portfolio holdings 126
Portfolio turnover rate 13%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
SS&C Technologies Holdings Inc 3.0
Teledyne Technologies Inc 2.6
OSI Systems Inc 2.5
Casey's General Stores Inc 1.9
LPL Financial Holdings Inc 1.9
Asset Allocation (% of net assets)
Common Stocks 98.0
Investment Companies 1.9
Investments Purchased with Cash Collateral from Securities Lending 0.9
Private Placements 0.4
OTC Purchased Options – Calls 0.0
Warrants 0.0
Other (1.2)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
SS&C Technologies Holdings Inc 3.0
Teledyne Technologies Inc 2.6
OSI Systems Inc 2.5
Casey's General Stores Inc 1.9
LPL Financial Holdings Inc 1.9
C000028947 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Triton Fund
Class Name Class T Shares
Trading Symbol JATTX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Triton Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Triton Fund
(Class T Shares/JATTX)		 $44 0.91%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 44
Expense Ratio, Percent 0.91% [63]
Net Assets $ 5,539,000,000
Holdings Count | Holding 126
Investment Company Portfolio Turnover 13.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $5,539M
Number of portfolio holdings 126
Portfolio turnover rate 13%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
SS&C Technologies Holdings Inc 3.0
Teledyne Technologies Inc 2.6
OSI Systems Inc 2.5
Casey's General Stores Inc 1.9
LPL Financial Holdings Inc 1.9
Asset Allocation (% of net assets)
Common Stocks 98.0
Investment Companies 1.9
Investments Purchased with Cash Collateral from Securities Lending 0.9
Private Placements 0.4
OTC Purchased Options – Calls 0.0
Warrants 0.0
Other (1.2)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
SS&C Technologies Holdings Inc 3.0
Teledyne Technologies Inc 2.6
OSI Systems Inc 2.5
Casey's General Stores Inc 1.9
LPL Financial Holdings Inc 1.9
C000100475 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Venture Fund
Class Name Class A Shares
Trading Symbol JVTAX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Venture Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Venture Fund
(Class A Shares/JVTAX)		 $50 1.04%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 50
Expense Ratio, Percent 1.04% [64]
Net Assets $ 2,890,000,000
Holdings Count | Holding 140
Investment Company Portfolio Turnover 15.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $2,890M
Number of portfolio holdings 140
Portfolio turnover rate 15%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Stride Inc 3.0
SS&C Technologies Holdings Inc 2.5
Descartes Systems Group Inc/The 2.0
OSI Systems Inc 2.0
LPL Financial Holdings Inc 1.8
Asset Allocation (% of net assets)
Common Stocks 97.5
Investment Companies 2.0
Investments Purchased with Cash Collateral from Securities Lending 1.1
Private Placements 0.7
OTC Purchased Options – Calls 0.0
Convertible Corporate Bonds 0.0
Other (1.3)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Stride Inc 3.0
SS&C Technologies Holdings Inc 2.5
Descartes Systems Group Inc/The 2.0
OSI Systems Inc 2.0
LPL Financial Holdings Inc 1.8
C000100476 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Venture Fund
Class Name Class C Shares
Trading Symbol JVTCX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Venture Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Venture Fund
(Class C Shares/JVTCX)		 $88 1.85%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 88
Expense Ratio, Percent 1.85% [65]
Net Assets $ 2,890,000,000
Holdings Count | Holding 140
Investment Company Portfolio Turnover 15.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $2,890M
Number of portfolio holdings 140
Portfolio turnover rate 15%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Stride Inc 3.0
SS&C Technologies Holdings Inc 2.5
Descartes Systems Group Inc/The 2.0
OSI Systems Inc 2.0
LPL Financial Holdings Inc 1.8
Asset Allocation (% of net assets)
Common Stocks 97.5
Investment Companies 2.0
Investments Purchased with Cash Collateral from Securities Lending 1.1
Private Placements 0.7
OTC Purchased Options – Calls 0.0
Convertible Corporate Bonds 0.0
Other (1.3)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Stride Inc 3.0
SS&C Technologies Holdings Inc 2.5
Descartes Systems Group Inc/The 2.0
OSI Systems Inc 2.0
LPL Financial Holdings Inc 1.8
C000083533 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Venture Fund
Class Name Class D Shares
Trading Symbol JANVX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Venture Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/reports. You can also request this information by contacting us at 1-800-525-3713.
Additional Information Phone Number 1-800-525-3713
Additional Information Website janushenderson.com/reports
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Venture Fund
(Class D Shares/JANVX)		 $38 0.79%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 38
Expense Ratio, Percent 0.79% [66]
Net Assets $ 2,890,000,000
Holdings Count | Holding 140
Investment Company Portfolio Turnover 15.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $2,890M
Number of portfolio holdings 140
Portfolio turnover rate 15%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Stride Inc 3.0
SS&C Technologies Holdings Inc 2.5
Descartes Systems Group Inc/The 2.0
OSI Systems Inc 2.0
LPL Financial Holdings Inc 1.8
Asset Allocation (% of net assets)
Common Stocks 97.5
Investment Companies 2.0
Investments Purchased with Cash Collateral from Securities Lending 1.1
Private Placements 0.7
OTC Purchased Options – Calls 0.0
Convertible Corporate Bonds 0.0
Other (1.3)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Stride Inc 3.0
SS&C Technologies Holdings Inc 2.5
Descartes Systems Group Inc/The 2.0
OSI Systems Inc 2.0
LPL Financial Holdings Inc 1.8
C000100477 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Venture Fund
Class Name Class I Shares
Trading Symbol JVTIX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Venture Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Venture Fund
(Class I Shares/JVTIX)		 $37 0.78%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 37
Expense Ratio, Percent 0.78% [67]
Net Assets $ 2,890,000,000
Holdings Count | Holding 140
Investment Company Portfolio Turnover 15.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $2,890M
Number of portfolio holdings 140
Portfolio turnover rate 15%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Stride Inc 3.0
SS&C Technologies Holdings Inc 2.5
Descartes Systems Group Inc/The 2.0
OSI Systems Inc 2.0
LPL Financial Holdings Inc 1.8
Asset Allocation (% of net assets)
Common Stocks 97.5
Investment Companies 2.0
Investments Purchased with Cash Collateral from Securities Lending 1.1
Private Placements 0.7
OTC Purchased Options – Calls 0.0
Convertible Corporate Bonds 0.0
Other (1.3)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Stride Inc 3.0
SS&C Technologies Holdings Inc 2.5
Descartes Systems Group Inc/The 2.0
OSI Systems Inc 2.0
LPL Financial Holdings Inc 1.8
C000114881 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Venture Fund
Class Name Class N Shares
Trading Symbol JVTNX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Venture Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Venture Fund
(Class N Shares/JVTNX)		 $32 0.67%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 32
Expense Ratio, Percent 0.67% [68]
Net Assets $ 2,890,000,000
Holdings Count | Holding 140
Investment Company Portfolio Turnover 15.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $2,890M
Number of portfolio holdings 140
Portfolio turnover rate 15%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Stride Inc 3.0
SS&C Technologies Holdings Inc 2.5
Descartes Systems Group Inc/The 2.0
OSI Systems Inc 2.0
LPL Financial Holdings Inc 1.8
Asset Allocation (% of net assets)
Common Stocks 97.5
Investment Companies 2.0
Investments Purchased with Cash Collateral from Securities Lending 1.1
Private Placements 0.7
OTC Purchased Options – Calls 0.0
Convertible Corporate Bonds 0.0
Other (1.3)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Stride Inc 3.0
SS&C Technologies Holdings Inc 2.5
Descartes Systems Group Inc/The 2.0
OSI Systems Inc 2.0
LPL Financial Holdings Inc 1.8
C000100478 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Venture Fund
Class Name Class S Shares
Trading Symbol JVTSX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Venture Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Venture Fund
(Class S Shares/JVTSX)		 $56 1.18%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 56
Expense Ratio, Percent 1.18% [69]
Net Assets $ 2,890,000,000
Holdings Count | Holding 140
Investment Company Portfolio Turnover 15.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $2,890M
Number of portfolio holdings 140
Portfolio turnover rate 15%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Stride Inc 3.0
SS&C Technologies Holdings Inc 2.5
Descartes Systems Group Inc/The 2.0
OSI Systems Inc 2.0
LPL Financial Holdings Inc 1.8
Asset Allocation (% of net assets)
Common Stocks 97.5
Investment Companies 2.0
Investments Purchased with Cash Collateral from Securities Lending 1.1
Private Placements 0.7
OTC Purchased Options – Calls 0.0
Convertible Corporate Bonds 0.0
Other (1.3)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Stride Inc 3.0
SS&C Technologies Holdings Inc 2.5
Descartes Systems Group Inc/The 2.0
OSI Systems Inc 2.0
LPL Financial Holdings Inc 1.8
C000028950 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Venture Fund
Class Name Class T Shares
Trading Symbol JAVTX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Venture Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Venture Fund
(Class T Shares/JAVTX)		 $43 0.90%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 43
Expense Ratio, Percent 0.90% [70]
Net Assets $ 2,890,000,000
Holdings Count | Holding 140
Investment Company Portfolio Turnover 15.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $2,890M
Number of portfolio holdings 140
Portfolio turnover rate 15%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Stride Inc 3.0
SS&C Technologies Holdings Inc 2.5
Descartes Systems Group Inc/The 2.0
OSI Systems Inc 2.0
LPL Financial Holdings Inc 1.8
Asset Allocation (% of net assets)
Common Stocks 97.5
Investment Companies 2.0
Investments Purchased with Cash Collateral from Securities Lending 1.1
Private Placements 0.7
OTC Purchased Options – Calls 0.0
Convertible Corporate Bonds 0.0
Other (1.3)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Stride Inc 3.0
SS&C Technologies Holdings Inc 2.5
Descartes Systems Group Inc/The 2.0
OSI Systems Inc 2.0
LPL Financial Holdings Inc 1.8
C000077732 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Research Fund
Class Name Class A Shares
Trading Symbol JDWAX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Research Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Research Fund
(Class A Shares/JDWAX)		 $55 1.11%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 55
Expense Ratio, Percent 1.11% [71]
Net Assets $ 3,765,000,000
Holdings Count | Holding 116
Investment Company Portfolio Turnover 17.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $3,765M
Number of portfolio holdings 116
Portfolio turnover rate 17%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 5.0
NVIDIA Corp 4.9
Apple Inc 3.3
Alphabet Inc - Class C 3.2
Amazon.com Inc 3.1
Asset Allocation (% of net assets)
Common Stocks 99.5
Preferred Stocks 0.5
Investments Purchased with Cash Collateral from Securities Lending 0.4
Investment Companies 0.1
Private Placements 0.0
Other (0.5)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 5.0
NVIDIA Corp 4.9
Apple Inc 3.3
Alphabet Inc - Class C 3.2
Amazon.com Inc 3.1
C000077733 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Research Fund
Class Name Class C Shares
Trading Symbol JWWCX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Research Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Research Fund
(Class C Shares/JWWCX)		 $95 1.91%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 95
Expense Ratio, Percent 1.91% [72]
Net Assets $ 3,765,000,000
Holdings Count | Holding 116
Investment Company Portfolio Turnover 17.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $3,765M
Number of portfolio holdings 116
Portfolio turnover rate 17%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 5.0
NVIDIA Corp 4.9
Apple Inc 3.3
Alphabet Inc - Class C 3.2
Amazon.com Inc 3.1
Asset Allocation (% of net assets)
Common Stocks 99.5
Preferred Stocks 0.5
Investments Purchased with Cash Collateral from Securities Lending 0.4
Investment Companies 0.1
Private Placements 0.0
Other (0.5)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 5.0
NVIDIA Corp 4.9
Apple Inc 3.3
Alphabet Inc - Class C 3.2
Amazon.com Inc 3.1
C000083534 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Research Fund
Class Name Class D Shares
Trading Symbol JANWX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Research Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/reports. You can also request this information by contacting us at 1-800-525-3713.
Additional Information Phone Number 1-800-525-3713
Additional Information Website janushenderson.com/reports
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Research Fund
(Class D Shares/JANWX)		 $42 0.84%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 42
Expense Ratio, Percent 0.84% [73]
Net Assets $ 3,765,000,000
Holdings Count | Holding 116
Investment Company Portfolio Turnover 17.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $3,765M
Number of portfolio holdings 116
Portfolio turnover rate 17%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 5.0
NVIDIA Corp 4.9
Apple Inc 3.3
Alphabet Inc - Class C 3.2
Amazon.com Inc 3.1
Asset Allocation (% of net assets)
Common Stocks 99.5
Preferred Stocks 0.5
Investments Purchased with Cash Collateral from Securities Lending 0.4
Investment Companies 0.1
Private Placements 0.0
Other (0.5)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 5.0
NVIDIA Corp 4.9
Apple Inc 3.3
Alphabet Inc - Class C 3.2
Amazon.com Inc 3.1
C000077734 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Research Fund
Class Name Class I Shares
Trading Symbol JWWFX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Research Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Research Fund
(Class I Shares/JWWFX)		 $40 0.80%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 40
Expense Ratio, Percent 0.80% [74]
Net Assets $ 3,765,000,000
Holdings Count | Holding 116
Investment Company Portfolio Turnover 17.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $3,765M
Number of portfolio holdings 116
Portfolio turnover rate 17%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 5.0
NVIDIA Corp 4.9
Apple Inc 3.3
Alphabet Inc - Class C 3.2
Amazon.com Inc 3.1
Asset Allocation (% of net assets)
Common Stocks 99.5
Preferred Stocks 0.5
Investments Purchased with Cash Collateral from Securities Lending 0.4
Investment Companies 0.1
Private Placements 0.0
Other (0.5)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 5.0
NVIDIA Corp 4.9
Apple Inc 3.3
Alphabet Inc - Class C 3.2
Amazon.com Inc 3.1
C000114882 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Research Fund
Class Name Class N Shares
Trading Symbol JDWNX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Research Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Research Fund
(Class N Shares/JDWNX)		 $37 0.74%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 37
Expense Ratio, Percent 0.74% [75]
Net Assets $ 3,765,000,000
Holdings Count | Holding 116
Investment Company Portfolio Turnover 17.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $3,765M
Number of portfolio holdings 116
Portfolio turnover rate 17%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 5.0
NVIDIA Corp 4.9
Apple Inc 3.3
Alphabet Inc - Class C 3.2
Amazon.com Inc 3.1
Asset Allocation (% of net assets)
Common Stocks 99.5
Preferred Stocks 0.5
Investments Purchased with Cash Collateral from Securities Lending 0.4
Investment Companies 0.1
Private Placements 0.0
Other (0.5)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 5.0
NVIDIA Corp 4.9
Apple Inc 3.3
Alphabet Inc - Class C 3.2
Amazon.com Inc 3.1
C000077735 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Research Fund
Class Name Class R Shares
Trading Symbol JDWRX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Research Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Research Fund
(Class R Shares/JDWRX)		 $74 1.49%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 74
Expense Ratio, Percent 1.49% [76]
Net Assets $ 3,765,000,000
Holdings Count | Holding 116
Investment Company Portfolio Turnover 17.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $3,765M
Number of portfolio holdings 116
Portfolio turnover rate 17%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 5.0
NVIDIA Corp 4.9
Apple Inc 3.3
Alphabet Inc - Class C 3.2
Amazon.com Inc 3.1
Asset Allocation (% of net assets)
Common Stocks 99.5
Preferred Stocks 0.5
Investments Purchased with Cash Collateral from Securities Lending 0.4
Investment Companies 0.1
Private Placements 0.0
Other (0.5)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 5.0
NVIDIA Corp 4.9
Apple Inc 3.3
Alphabet Inc - Class C 3.2
Amazon.com Inc 3.1
C000077736 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Research Fund
Class Name Class S Shares
Trading Symbol JWGRX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Research Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Research Fund
(Class S Shares/JWGRX)		 $61 1.22%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 61
Expense Ratio, Percent 1.22% [77]
Net Assets $ 3,765,000,000
Holdings Count | Holding 116
Investment Company Portfolio Turnover 17.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $3,765M
Number of portfolio holdings 116
Portfolio turnover rate 17%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 5.0
NVIDIA Corp 4.9
Apple Inc 3.3
Alphabet Inc - Class C 3.2
Amazon.com Inc 3.1
Asset Allocation (% of net assets)
Common Stocks 99.5
Preferred Stocks 0.5
Investments Purchased with Cash Collateral from Securities Lending 0.4
Investment Companies 0.1
Private Placements 0.0
Other (0.5)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 5.0
NVIDIA Corp 4.9
Apple Inc 3.3
Alphabet Inc - Class C 3.2
Amazon.com Inc 3.1
C000028951 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Research Fund
Class Name Class T Shares
Trading Symbol JAWWX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Research Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Research Fund
(Class T Shares/JAWWX)		 $47 0.95%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 47
Expense Ratio, Percent 0.95% [78]
Net Assets $ 3,765,000,000
Holdings Count | Holding 116
Investment Company Portfolio Turnover 17.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $3,765M
Number of portfolio holdings 116
Portfolio turnover rate 17%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 5.0
NVIDIA Corp 4.9
Apple Inc 3.3
Alphabet Inc - Class C 3.2
Amazon.com Inc 3.1
Asset Allocation (% of net assets)
Common Stocks 99.5
Preferred Stocks 0.5
Investments Purchased with Cash Collateral from Securities Lending 0.4
Investment Companies 0.1
Private Placements 0.0
Other (0.5)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 5.0
NVIDIA Corp 4.9
Apple Inc 3.3
Alphabet Inc - Class C 3.2
Amazon.com Inc 3.1
C000077737 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Enterprise Fund
Class Name Class A Shares
Trading Symbol JDMAX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Enterprise Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Enterprise Fund
(Class A Shares/JDMAX)		 $55 1.12%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 55
Expense Ratio, Percent 1.12% [79]
Net Assets $ 21,270,000,000
Holdings Count | Holding 79
Investment Company Portfolio Turnover 8.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $21,270M
Number of portfolio holdings 79
Portfolio turnover rate 8%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Constellation Software Inc/Canada 4.7
SS&C Technologies Holdings Inc 3.8
Boston Scientific Corp 3.4
Intact Financial Corp 3.3
GoDaddy Inc 3.2
Asset Allocation (% of net assets)
Common Stocks 96.5
Investment Companies 3.6
Other (0.1)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Constellation Software Inc/Canada 4.7
SS&C Technologies Holdings Inc 3.8
Boston Scientific Corp 3.4
Intact Financial Corp 3.3
GoDaddy Inc 3.2
C000077738 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Enterprise Fund
Class Name Class C Shares
Trading Symbol JGRCX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Enterprise Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Enterprise Fund
(Class C Shares/JGRCX)		 $81 1.66%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 81
Expense Ratio, Percent 1.66% [80]
Net Assets $ 21,270,000,000
Holdings Count | Holding 79
Investment Company Portfolio Turnover 8.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $21,270M
Number of portfolio holdings 79
Portfolio turnover rate 8%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Constellation Software Inc/Canada 4.7
SS&C Technologies Holdings Inc 3.8
Boston Scientific Corp 3.4
Intact Financial Corp 3.3
GoDaddy Inc 3.2
Asset Allocation (% of net assets)
Common Stocks 96.5
Investment Companies 3.6
Other (0.1)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Constellation Software Inc/Canada 4.7
SS&C Technologies Holdings Inc 3.8
Boston Scientific Corp 3.4
Intact Financial Corp 3.3
GoDaddy Inc 3.2
C000083535 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Enterprise Fund
Class Name Class D Shares
Trading Symbol JANEX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Enterprise Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/reports. You can also request this information by contacting us at 1-800-525-3713.
Additional Information Phone Number 1-800-525-3713
Additional Information Website janushenderson.com/reports
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Enterprise Fund
(Class D Shares/JANEX)		 $38 0.78%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 38
Expense Ratio, Percent 0.78% [81]
Net Assets $ 21,270,000,000
Holdings Count | Holding 79
Investment Company Portfolio Turnover 8.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $21,270M
Number of portfolio holdings 79
Portfolio turnover rate 8%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Constellation Software Inc/Canada 4.7
SS&C Technologies Holdings Inc 3.8
Boston Scientific Corp 3.4
Intact Financial Corp 3.3
GoDaddy Inc 3.2
Asset Allocation (% of net assets)
Common Stocks 96.5
Investment Companies 3.6
Other (0.1)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Constellation Software Inc/Canada 4.7
SS&C Technologies Holdings Inc 3.8
Boston Scientific Corp 3.4
Intact Financial Corp 3.3
GoDaddy Inc 3.2
C000077739 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Enterprise Fund
Class Name Class I Shares
Trading Symbol JMGRX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Enterprise Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Enterprise Fund
(Class I Shares/JMGRX)		 $37 0.76%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 37
Expense Ratio, Percent 0.76% [82]
Net Assets $ 21,270,000,000
Holdings Count | Holding 79
Investment Company Portfolio Turnover 8.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $21,270M
Number of portfolio holdings 79
Portfolio turnover rate 8%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Constellation Software Inc/Canada 4.7
SS&C Technologies Holdings Inc 3.8
Boston Scientific Corp 3.4
Intact Financial Corp 3.3
GoDaddy Inc 3.2
Asset Allocation (% of net assets)
Common Stocks 96.5
Investment Companies 3.6
Other (0.1)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Constellation Software Inc/Canada 4.7
SS&C Technologies Holdings Inc 3.8
Boston Scientific Corp 3.4
Intact Financial Corp 3.3
GoDaddy Inc 3.2
C000114883 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Enterprise Fund
Class Name Class N Shares
Trading Symbol JDMNX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Enterprise Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Enterprise Fund
(Class N Shares/JDMNX)		 $32 0.66%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 32
Expense Ratio, Percent 0.66% [83]
Net Assets $ 21,270,000,000
Holdings Count | Holding 79
Investment Company Portfolio Turnover 8.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $21,270M
Number of portfolio holdings 79
Portfolio turnover rate 8%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Constellation Software Inc/Canada 4.7
SS&C Technologies Holdings Inc 3.8
Boston Scientific Corp 3.4
Intact Financial Corp 3.3
GoDaddy Inc 3.2
Asset Allocation (% of net assets)
Common Stocks 96.5
Investment Companies 3.6
Other (0.1)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Constellation Software Inc/Canada 4.7
SS&C Technologies Holdings Inc 3.8
Boston Scientific Corp 3.4
Intact Financial Corp 3.3
GoDaddy Inc 3.2
C000077740 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Enterprise Fund
Class Name Class R Shares
Trading Symbol JDMRX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Enterprise Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Enterprise Fund
(Class R Shares/JDMRX)		 $69 1.41%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 69
Expense Ratio, Percent 1.41% [84]
Net Assets $ 21,270,000,000
Holdings Count | Holding 79
Investment Company Portfolio Turnover 8.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $21,270M
Number of portfolio holdings 79
Portfolio turnover rate 8%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Constellation Software Inc/Canada 4.7
SS&C Technologies Holdings Inc 3.8
Boston Scientific Corp 3.4
Intact Financial Corp 3.3
GoDaddy Inc 3.2
Asset Allocation (% of net assets)
Common Stocks 96.5
Investment Companies 3.6
Other (0.1)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Constellation Software Inc/Canada 4.7
SS&C Technologies Holdings Inc 3.8
Boston Scientific Corp 3.4
Intact Financial Corp 3.3
GoDaddy Inc 3.2
C000077741 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Enterprise Fund
Class Name Class S Shares
Trading Symbol JGRTX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Enterprise Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Enterprise Fund
(Class S Shares/JGRTX)		 $57 1.16%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 57
Expense Ratio, Percent 1.16% [85]
Net Assets $ 21,270,000,000
Holdings Count | Holding 79
Investment Company Portfolio Turnover 8.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $21,270M
Number of portfolio holdings 79
Portfolio turnover rate 8%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Constellation Software Inc/Canada 4.7
SS&C Technologies Holdings Inc 3.8
Boston Scientific Corp 3.4
Intact Financial Corp 3.3
GoDaddy Inc 3.2
Asset Allocation (% of net assets)
Common Stocks 96.5
Investment Companies 3.6
Other (0.1)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Constellation Software Inc/Canada 4.7
SS&C Technologies Holdings Inc 3.8
Boston Scientific Corp 3.4
Intact Financial Corp 3.3
GoDaddy Inc 3.2
C000028952 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Enterprise Fund
Class Name Class T Shares
Trading Symbol JAENX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Enterprise Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Enterprise Fund
(Class T Shares/JAENX)		 $44 0.90%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 44
Expense Ratio, Percent 0.90% [86]
Net Assets $ 21,270,000,000
Holdings Count | Holding 79
Investment Company Portfolio Turnover 8.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $21,270M
Number of portfolio holdings 79
Portfolio turnover rate 8%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Constellation Software Inc/Canada 4.7
SS&C Technologies Holdings Inc 3.8
Boston Scientific Corp 3.4
Intact Financial Corp 3.3
GoDaddy Inc 3.2
Asset Allocation (% of net assets)
Common Stocks 96.5
Investment Companies 3.6
Other (0.1)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Constellation Software Inc/Canada 4.7
SS&C Technologies Holdings Inc 3.8
Boston Scientific Corp 3.4
Intact Financial Corp 3.3
GoDaddy Inc 3.2
C000077752 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Life Sciences Fund
Class Name Class A Shares
Trading Symbol JFNAX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Life Sciences Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Life Sciences Fund
(Class A Shares/JFNAX)		 $47 1.00%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 47
Expense Ratio, Percent 1.00% [87]
Net Assets $ 4,712,000,000
Holdings Count | Holding 115
Investment Company Portfolio Turnover 14.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $4,712M
Number of portfolio holdings 115
Portfolio turnover rate 14%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Eli Lilly & Co 9.4
UnitedHealth Group Inc 6.9
AstraZeneca PLC 4.0
Johnson & Johnson 3.6
Boston Scientific Corp 3.1
Asset Allocation (% of net assets)
Common Stocks 98.5
Private Placements 0.9
Investment Companies 0.3
Investments Purchased with Cash Collateral from Securities Lending 0.1
Convertible Corporate Bonds 0.0
Warrants 0.0
Rights 0.0
Other 0.2
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Eli Lilly & Co 9.4
UnitedHealth Group Inc 6.9
AstraZeneca PLC 4.0
Johnson & Johnson 3.6
Boston Scientific Corp 3.1
C000077753 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Life Sciences Fund
Class Name Class C Shares
Trading Symbol JFNCX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Life Sciences Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Life Sciences Fund
(Class C Shares/JFNCX)		 $82 1.73%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 82
Expense Ratio, Percent 1.73% [88]
Net Assets $ 4,712,000,000
Holdings Count | Holding 115
Investment Company Portfolio Turnover 14.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $4,712M
Number of portfolio holdings 115
Portfolio turnover rate 14%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Eli Lilly & Co 9.4
UnitedHealth Group Inc 6.9
AstraZeneca PLC 4.0
Johnson & Johnson 3.6
Boston Scientific Corp 3.1
Asset Allocation (% of net assets)
Common Stocks 98.5
Private Placements 0.9
Investment Companies 0.3
Investments Purchased with Cash Collateral from Securities Lending 0.1
Convertible Corporate Bonds 0.0
Warrants 0.0
Rights 0.0
Other 0.2
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Eli Lilly & Co 9.4
UnitedHealth Group Inc 6.9
AstraZeneca PLC 4.0
Johnson & Johnson 3.6
Boston Scientific Corp 3.1
C000083538 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Life Sciences Fund
Class Name Class D Shares
Trading Symbol JNGLX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Life Sciences Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/reports. You can also request this information by contacting us at 1-800-525-3713.
Additional Information Phone Number 1-800-525-3713
Additional Information Website janushenderson.com/reports
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Life Sciences Fund
(Class D Shares/JNGLX)		 $38 0.80%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 38
Expense Ratio, Percent 0.80% [89]
Net Assets $ 4,712,000,000
Holdings Count | Holding 115
Investment Company Portfolio Turnover 14.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $4,712M
Number of portfolio holdings 115
Portfolio turnover rate 14%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Eli Lilly & Co 9.4
UnitedHealth Group Inc 6.9
AstraZeneca PLC 4.0
Johnson & Johnson 3.6
Boston Scientific Corp 3.1
Asset Allocation (% of net assets)
Common Stocks 98.5
Private Placements 0.9
Investment Companies 0.3
Investments Purchased with Cash Collateral from Securities Lending 0.1
Convertible Corporate Bonds 0.0
Warrants 0.0
Rights 0.0
Other 0.2
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Eli Lilly & Co 9.4
UnitedHealth Group Inc 6.9
AstraZeneca PLC 4.0
Johnson & Johnson 3.6
Boston Scientific Corp 3.1
C000077754 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Life Sciences Fund
Class Name Class I Shares
Trading Symbol JFNIX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Life Sciences Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Life Sciences Fund
(Class I Shares/JFNIX)		 $37 0.79%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 37
Expense Ratio, Percent 0.79% [90]
Net Assets $ 4,712,000,000
Holdings Count | Holding 115
Investment Company Portfolio Turnover 14.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $4,712M
Number of portfolio holdings 115
Portfolio turnover rate 14%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Eli Lilly & Co 9.4
UnitedHealth Group Inc 6.9
AstraZeneca PLC 4.0
Johnson & Johnson 3.6
Boston Scientific Corp 3.1
Asset Allocation (% of net assets)
Common Stocks 98.5
Private Placements 0.9
Investment Companies 0.3
Investments Purchased with Cash Collateral from Securities Lending 0.1
Convertible Corporate Bonds 0.0
Warrants 0.0
Rights 0.0
Other 0.2
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Eli Lilly & Co 9.4
UnitedHealth Group Inc 6.9
AstraZeneca PLC 4.0
Johnson & Johnson 3.6
Boston Scientific Corp 3.1
C000198286 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Life Sciences Fund
Class Name Class N Shares
Trading Symbol JFNNX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Life Sciences Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Life Sciences Fund
(Class N Shares/JFNNX)		 $32 0.67%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 32
Expense Ratio, Percent 0.67% [91]
Net Assets $ 4,712,000,000
Holdings Count | Holding 115
Investment Company Portfolio Turnover 14.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $4,712M
Number of portfolio holdings 115
Portfolio turnover rate 14%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Eli Lilly & Co 9.4
UnitedHealth Group Inc 6.9
AstraZeneca PLC 4.0
Johnson & Johnson 3.6
Boston Scientific Corp 3.1
Asset Allocation (% of net assets)
Common Stocks 98.5
Private Placements 0.9
Investment Companies 0.3
Investments Purchased with Cash Collateral from Securities Lending 0.1
Convertible Corporate Bonds 0.0
Warrants 0.0
Rights 0.0
Other 0.2
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Eli Lilly & Co 9.4
UnitedHealth Group Inc 6.9
AstraZeneca PLC 4.0
Johnson & Johnson 3.6
Boston Scientific Corp 3.1
C000077755 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Life Sciences Fund
Class Name Class S Shares
Trading Symbol JFNSX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Life Sciences Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Life Sciences Fund
(Class S Shares/JFNSX)		 $56 1.18%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 56
Expense Ratio, Percent 1.18% [92]
Net Assets $ 4,712,000,000
Holdings Count | Holding 115
Investment Company Portfolio Turnover 14.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $4,712M
Number of portfolio holdings 115
Portfolio turnover rate 14%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Eli Lilly & Co 9.4
UnitedHealth Group Inc 6.9
AstraZeneca PLC 4.0
Johnson & Johnson 3.6
Boston Scientific Corp 3.1
Asset Allocation (% of net assets)
Common Stocks 98.5
Private Placements 0.9
Investment Companies 0.3
Investments Purchased with Cash Collateral from Securities Lending 0.1
Convertible Corporate Bonds 0.0
Warrants 0.0
Rights 0.0
Other 0.2
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Eli Lilly & Co 9.4
UnitedHealth Group Inc 6.9
AstraZeneca PLC 4.0
Johnson & Johnson 3.6
Boston Scientific Corp 3.1
C000028956 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Life Sciences Fund
Class Name Class T Shares
Trading Symbol JAGLX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Life Sciences Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Life Sciences Fund
(Class T Shares/JAGLX)		 $43 0.91%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 43
Expense Ratio, Percent 0.91% [93]
Net Assets $ 4,712,000,000
Holdings Count | Holding 115
Investment Company Portfolio Turnover 14.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $4,712M
Number of portfolio holdings 115
Portfolio turnover rate 14%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Eli Lilly & Co 9.4
UnitedHealth Group Inc 6.9
AstraZeneca PLC 4.0
Johnson & Johnson 3.6
Boston Scientific Corp 3.1
Asset Allocation (% of net assets)
Common Stocks 98.5
Private Placements 0.9
Investment Companies 0.3
Investments Purchased with Cash Collateral from Securities Lending 0.1
Convertible Corporate Bonds 0.0
Warrants 0.0
Rights 0.0
Other 0.2
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Eli Lilly & Co 9.4
UnitedHealth Group Inc 6.9
AstraZeneca PLC 4.0
Johnson & Johnson 3.6
Boston Scientific Corp 3.1
C000077597 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Real Estate Fund
Class Name Class A Shares
Trading Symbol JERAX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Real Estate Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Real Estate Fund
(Class A Shares/JERAX)		 $48 1.01%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 48
Expense Ratio, Percent 1.01% [94]
Net Assets $ 302,000,000
Holdings Count | Holding 60
Investment Company Portfolio Turnover 28.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $302M
Number of portfolio holdings 60
Portfolio turnover rate 28%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Equinix Inc 5.6
Realty Income Corp 4.4
Public Storage 4.3
Digital Realty Trust Inc 4.2
Goodman Group 3.8
Asset Allocation (% of net assets)
Common Stocks 98.8
Investments Purchased with Cash Collateral from Securities Lending 0.9
Investment Companies 0.9
Other (0.6)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Equinix Inc 5.6
Realty Income Corp 4.4
Public Storage 4.3
Digital Realty Trust Inc 4.2
Goodman Group 3.8
C000077598 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Real Estate Fund
Class Name Class C Shares
Trading Symbol JERCX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Real Estate Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Real Estate Fund
(Class C Shares/JERCX)		 $83 1.75%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 83
Expense Ratio, Percent 1.75% [95]
Net Assets $ 302,000,000
Holdings Count | Holding 60
Investment Company Portfolio Turnover 28.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $302M
Number of portfolio holdings 60
Portfolio turnover rate 28%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Equinix Inc 5.6
Realty Income Corp 4.4
Public Storage 4.3
Digital Realty Trust Inc 4.2
Goodman Group 3.8
Asset Allocation (% of net assets)
Common Stocks 98.8
Investments Purchased with Cash Collateral from Securities Lending 0.9
Investment Companies 0.9
Other (0.6)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Equinix Inc 5.6
Realty Income Corp 4.4
Public Storage 4.3
Digital Realty Trust Inc 4.2
Goodman Group 3.8
C000083540 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Real Estate Fund
Class Name Class D Shares
Trading Symbol JNGSX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Real Estate Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/reports. You can also request this information by contacting us at 1-800-525-3713.
Additional Information Phone Number 1-800-525-3713
Additional Information Website janushenderson.com/reports
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Real Estate Fund
(Class D Shares/JNGSX)		 $38 0.81%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 38
Expense Ratio, Percent 0.81% [96]
Net Assets $ 302,000,000
Holdings Count | Holding 60
Investment Company Portfolio Turnover 28.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $302M
Number of portfolio holdings 60
Portfolio turnover rate 28%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Equinix Inc 5.6
Realty Income Corp 4.4
Public Storage 4.3
Digital Realty Trust Inc 4.2
Goodman Group 3.8
Asset Allocation (% of net assets)
Common Stocks 98.8
Investments Purchased with Cash Collateral from Securities Lending 0.9
Investment Companies 0.9
Other (0.6)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Equinix Inc 5.6
Realty Income Corp 4.4
Public Storage 4.3
Digital Realty Trust Inc 4.2
Goodman Group 3.8
C000077599 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Real Estate Fund
Class Name Class I Shares
Trading Symbol JERIX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Real Estate Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Real Estate Fund
(Class I Shares/JERIX)		 $36 0.76%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 36
Expense Ratio, Percent 0.76% [97]
Net Assets $ 302,000,000
Holdings Count | Holding 60
Investment Company Portfolio Turnover 28.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $302M
Number of portfolio holdings 60
Portfolio turnover rate 28%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Equinix Inc 5.6
Realty Income Corp 4.4
Public Storage 4.3
Digital Realty Trust Inc 4.2
Goodman Group 3.8
Asset Allocation (% of net assets)
Common Stocks 98.8
Investments Purchased with Cash Collateral from Securities Lending 0.9
Investment Companies 0.9
Other (0.6)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Equinix Inc 5.6
Realty Income Corp 4.4
Public Storage 4.3
Digital Realty Trust Inc 4.2
Goodman Group 3.8
C000198287 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Real Estate Fund
Class Name Class N Shares
Trading Symbol JERNX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Real Estate Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Real Estate Fund
(Class N Shares/JERNX)		 $32 0.67%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 32
Expense Ratio, Percent 0.67% [98]
Net Assets $ 302,000,000
Holdings Count | Holding 60
Investment Company Portfolio Turnover 28.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $302M
Number of portfolio holdings 60
Portfolio turnover rate 28%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Equinix Inc 5.6
Realty Income Corp 4.4
Public Storage 4.3
Digital Realty Trust Inc 4.2
Goodman Group 3.8
Asset Allocation (% of net assets)
Common Stocks 98.8
Investments Purchased with Cash Collateral from Securities Lending 0.9
Investment Companies 0.9
Other (0.6)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Equinix Inc 5.6
Realty Income Corp 4.4
Public Storage 4.3
Digital Realty Trust Inc 4.2
Goodman Group 3.8
C000077600 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Real Estate Fund
Class Name Class S Shares
Trading Symbol JERSX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Real Estate Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Real Estate Fund
(Class S Shares/JERSX)		 $55 1.17%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 55
Expense Ratio, Percent 1.17% [99]
Net Assets $ 302,000,000
Holdings Count | Holding 60
Investment Company Portfolio Turnover 28.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $302M
Number of portfolio holdings 60
Portfolio turnover rate 28%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Equinix Inc 5.6
Realty Income Corp 4.4
Public Storage 4.3
Digital Realty Trust Inc 4.2
Goodman Group 3.8
Asset Allocation (% of net assets)
Common Stocks 98.8
Investments Purchased with Cash Collateral from Securities Lending 0.9
Investment Companies 0.9
Other (0.6)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Equinix Inc 5.6
Realty Income Corp 4.4
Public Storage 4.3
Digital Realty Trust Inc 4.2
Goodman Group 3.8
C000077601 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Real Estate Fund
Class Name Class T Shares
Trading Symbol JERTX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Real Estate Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Real Estate Fund
(Class T Shares/JERTX)		 $43 0.91%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 43
Expense Ratio, Percent 0.91% [100]
Net Assets $ 302,000,000
Holdings Count | Holding 60
Investment Company Portfolio Turnover 28.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $302M
Number of portfolio holdings 60
Portfolio turnover rate 28%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Equinix Inc 5.6
Realty Income Corp 4.4
Public Storage 4.3
Digital Realty Trust Inc 4.2
Goodman Group 3.8
Asset Allocation (% of net assets)
Common Stocks 98.8
Investments Purchased with Cash Collateral from Securities Lending 0.9
Investment Companies 0.9
Other (0.6)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Equinix Inc 5.6
Realty Income Corp 4.4
Public Storage 4.3
Digital Realty Trust Inc 4.2
Goodman Group 3.8
C000077618 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Forty Fund
Class Name Class A Shares
Trading Symbol JDCAX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Forty Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Forty Fund
(Class A Shares/JDCAX)		 $42 0.87%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 42
Expense Ratio, Percent 0.87% [101]
Net Assets $ 19,733,000,000
Holdings Count | Holding 36
Investment Company Portfolio Turnover 19.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $19,733M
Number of portfolio holdings 36
Portfolio turnover rate 19%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 10.6
Amazon.com Inc 8.3
NVIDIA Corp 6.0
Mastercard Inc - Class A 5.7
Apple Inc 5.5
Asset Allocation (% of net assets)
Common Stocks 99.5
Investment Companies 0.5
Other (0.0)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 10.6
Amazon.com Inc 8.3
NVIDIA Corp 6.0
Mastercard Inc - Class A 5.7
Apple Inc 5.5
C000077619 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Forty Fund
Class Name Class C Shares
Trading Symbol JACCX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Forty Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Forty Fund
(Class C Shares/JACCX)		 $72 1.50%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 72
Expense Ratio, Percent 1.50% [102]
Net Assets $ 19,733,000,000
Holdings Count | Holding 36
Investment Company Portfolio Turnover 19.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $19,733M
Number of portfolio holdings 36
Portfolio turnover rate 19%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 10.6
Amazon.com Inc 8.3
NVIDIA Corp 6.0
Mastercard Inc - Class A 5.7
Apple Inc 5.5
Asset Allocation (% of net assets)
Common Stocks 99.5
Investment Companies 0.5
Other (0.0)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 10.6
Amazon.com Inc 8.3
NVIDIA Corp 6.0
Mastercard Inc - Class A 5.7
Apple Inc 5.5
C000177054 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Forty Fund
Class Name Class D Shares
Trading Symbol JFRDX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Forty Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/reports. You can also request this information by contacting us at 1-800-525-3713.
Additional Information Phone Number 1-800-525-3713
Additional Information Website janushenderson.com/reports
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Forty Fund
(Class D Shares/JFRDX)		 $31 0.65%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 31
Expense Ratio, Percent 0.65% [103]
Net Assets $ 19,733,000,000
Holdings Count | Holding 36
Investment Company Portfolio Turnover 19.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $19,733M
Number of portfolio holdings 36
Portfolio turnover rate 19%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 10.6
Amazon.com Inc 8.3
NVIDIA Corp 6.0
Mastercard Inc - Class A 5.7
Apple Inc 5.5
Asset Allocation (% of net assets)
Common Stocks 99.5
Investment Companies 0.5
Other (0.0)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 10.6
Amazon.com Inc 8.3
NVIDIA Corp 6.0
Mastercard Inc - Class A 5.7
Apple Inc 5.5
C000077620 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Forty Fund
Class Name Class I Shares
Trading Symbol JCAPX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Forty Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Forty Fund
(Class I Shares/JCAPX)		 $30 0.62%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 30
Expense Ratio, Percent 0.62% [104]
Net Assets $ 19,733,000,000
Holdings Count | Holding 36
Investment Company Portfolio Turnover 19.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $19,733M
Number of portfolio holdings 36
Portfolio turnover rate 19%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 10.6
Amazon.com Inc 8.3
NVIDIA Corp 6.0
Mastercard Inc - Class A 5.7
Apple Inc 5.5
Asset Allocation (% of net assets)
Common Stocks 99.5
Investment Companies 0.5
Other (0.0)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 10.6
Amazon.com Inc 8.3
NVIDIA Corp 6.0
Mastercard Inc - Class A 5.7
Apple Inc 5.5
C000114888 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Forty Fund
Class Name Class N Shares
Trading Symbol JFRNX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Forty Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Forty Fund
(Class N Shares/JFRNX)		 $26 0.54%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 26
Expense Ratio, Percent 0.54% [105]
Net Assets $ 19,733,000,000
Holdings Count | Holding 36
Investment Company Portfolio Turnover 19.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $19,733M
Number of portfolio holdings 36
Portfolio turnover rate 19%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 10.6
Amazon.com Inc 8.3
NVIDIA Corp 6.0
Mastercard Inc - Class A 5.7
Apple Inc 5.5
Asset Allocation (% of net assets)
Common Stocks 99.5
Investment Companies 0.5
Other (0.0)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 10.6
Amazon.com Inc 8.3
NVIDIA Corp 6.0
Mastercard Inc - Class A 5.7
Apple Inc 5.5
C000077621 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Forty Fund
Class Name Class R Shares
Trading Symbol JDCRX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Forty Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Forty Fund
(Class R Shares/JDCRX)		 $62 1.28%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 62
Expense Ratio, Percent 1.28% [106]
Net Assets $ 19,733,000,000
Holdings Count | Holding 36
Investment Company Portfolio Turnover 19.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $19,733M
Number of portfolio holdings 36
Portfolio turnover rate 19%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 10.6
Amazon.com Inc 8.3
NVIDIA Corp 6.0
Mastercard Inc - Class A 5.7
Apple Inc 5.5
Asset Allocation (% of net assets)
Common Stocks 99.5
Investment Companies 0.5
Other (0.0)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 10.6
Amazon.com Inc 8.3
NVIDIA Corp 6.0
Mastercard Inc - Class A 5.7
Apple Inc 5.5
C000077622 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Forty Fund
Class Name Class S Shares
Trading Symbol JARTX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Forty Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Forty Fund
(Class S Shares/JARTX)		 $49 1.02%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 49
Expense Ratio, Percent 1.02% [107]
Net Assets $ 19,733,000,000
Holdings Count | Holding 36
Investment Company Portfolio Turnover 19.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $19,733M
Number of portfolio holdings 36
Portfolio turnover rate 19%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 10.6
Amazon.com Inc 8.3
NVIDIA Corp 6.0
Mastercard Inc - Class A 5.7
Apple Inc 5.5
Asset Allocation (% of net assets)
Common Stocks 99.5
Investment Companies 0.5
Other (0.0)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 10.6
Amazon.com Inc 8.3
NVIDIA Corp 6.0
Mastercard Inc - Class A 5.7
Apple Inc 5.5
C000077623 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Forty Fund
Class Name Class T Shares
Trading Symbol JACTX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Forty Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Forty Fund
(Class T Shares/JACTX)		 $37 0.76%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 37
Expense Ratio, Percent 0.76% [108]
Net Assets $ 19,733,000,000
Holdings Count | Holding 36
Investment Company Portfolio Turnover 19.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $19,733M
Number of portfolio holdings 36
Portfolio turnover rate 19%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 10.6
Amazon.com Inc 8.3
NVIDIA Corp 6.0
Mastercard Inc - Class A 5.7
Apple Inc 5.5
Asset Allocation (% of net assets)
Common Stocks 99.5
Investment Companies 0.5
Other (0.0)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 10.6
Amazon.com Inc 8.3
NVIDIA Corp 6.0
Mastercard Inc - Class A 5.7
Apple Inc 5.5
C000183873 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Emerging Markets Fund
Class Name Class A Shares
Trading Symbol HEMAX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Emerging Markets Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Emerging Markets Fund
(Class A Shares/HEMAX)		 $68 1.40%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 68
Expense Ratio, Percent 1.40% [109]
Net Assets $ 32,000,000
Holdings Count | Holding 57
Investment Company Portfolio Turnover 28.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $32M
Number of portfolio holdings 57
Portfolio turnover rate 28%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 9.5
Tencent Holdings Ltd 4.5
Samsung Electronics Co Ltd 4.2
BYD Co Ltd 3.7
Full Truck Alliance Co (ADR) 3.7
Asset Allocation (% of net assets)
Common Stocks 97.4
Investment Companies 2.6
Private Placements 0.1
Other (0.1)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 9.5
Tencent Holdings Ltd 4.5
Samsung Electronics Co Ltd 4.2
BYD Co Ltd 3.7
Full Truck Alliance Co (ADR) 3.7
C000183875 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Emerging Markets Fund
Class Name Class C Shares
Trading Symbol HEMCX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Emerging Markets Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Emerging Markets Fund
(Class C Shares/HEMCX)		 $104 2.15%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 104
Expense Ratio, Percent 2.15% [110]
Net Assets $ 32,000,000
Holdings Count | Holding 57
Investment Company Portfolio Turnover 28.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $32M
Number of portfolio holdings 57
Portfolio turnover rate 28%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 9.5
Tencent Holdings Ltd 4.5
Samsung Electronics Co Ltd 4.2
BYD Co Ltd 3.7
Full Truck Alliance Co (ADR) 3.7
Asset Allocation (% of net assets)
Common Stocks 97.4
Investment Companies 2.6
Private Placements 0.1
Other (0.1)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 9.5
Tencent Holdings Ltd 4.5
Samsung Electronics Co Ltd 4.2
BYD Co Ltd 3.7
Full Truck Alliance Co (ADR) 3.7
C000183876 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Emerging Markets Fund
Class Name Class D Shares
Trading Symbol HEMDX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Emerging Markets Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/reports. You can also request this information by contacting us at 1-800-525-3713.
Additional Information Phone Number 1-800-525-3713
Additional Information Website janushenderson.com/reports
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Emerging Markets Fund
(Class D Shares/HEMDX)		 $57 1.18%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 57
Expense Ratio, Percent 1.18% [111]
Net Assets $ 32,000,000
Holdings Count | Holding 57
Investment Company Portfolio Turnover 28.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $32M
Number of portfolio holdings 57
Portfolio turnover rate 28%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 9.5
Tencent Holdings Ltd 4.5
Samsung Electronics Co Ltd 4.2
BYD Co Ltd 3.7
Full Truck Alliance Co (ADR) 3.7
Asset Allocation (% of net assets)
Common Stocks 97.4
Investment Companies 2.6
Private Placements 0.1
Other (0.1)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 9.5
Tencent Holdings Ltd 4.5
Samsung Electronics Co Ltd 4.2
BYD Co Ltd 3.7
Full Truck Alliance Co (ADR) 3.7
C000183877 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Emerging Markets Fund
Class Name Class I Shares
Trading Symbol HEMIX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Emerging Markets Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Emerging Markets Fund
(Class I Shares/HEMIX)		 $55 1.13%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 55
Expense Ratio, Percent 1.13% [112]
Net Assets $ 32,000,000
Holdings Count | Holding 57
Investment Company Portfolio Turnover 28.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $32M
Number of portfolio holdings 57
Portfolio turnover rate 28%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 9.5
Tencent Holdings Ltd 4.5
Samsung Electronics Co Ltd 4.2
BYD Co Ltd 3.7
Full Truck Alliance Co (ADR) 3.7
Asset Allocation (% of net assets)
Common Stocks 97.4
Investment Companies 2.6
Private Placements 0.1
Other (0.1)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 9.5
Tencent Holdings Ltd 4.5
Samsung Electronics Co Ltd 4.2
BYD Co Ltd 3.7
Full Truck Alliance Co (ADR) 3.7
C000183878 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Emerging Markets Fund
Class Name Class N Shares
Trading Symbol HEMRX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Emerging Markets Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Emerging Markets Fund
(Class N Shares/HEMRX)		 $50 1.04%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 50
Expense Ratio, Percent 1.04% [113]
Net Assets $ 32,000,000
Holdings Count | Holding 57
Investment Company Portfolio Turnover 28.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $32M
Number of portfolio holdings 57
Portfolio turnover rate 28%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 9.5
Tencent Holdings Ltd 4.5
Samsung Electronics Co Ltd 4.2
BYD Co Ltd 3.7
Full Truck Alliance Co (ADR) 3.7
Asset Allocation (% of net assets)
Common Stocks 97.4
Investment Companies 2.6
Private Placements 0.1
Other (0.1)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 9.5
Tencent Holdings Ltd 4.5
Samsung Electronics Co Ltd 4.2
BYD Co Ltd 3.7
Full Truck Alliance Co (ADR) 3.7
C000183880 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Emerging Markets Fund
Class Name Class S Shares
Trading Symbol HEMSX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Emerging Markets Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Emerging Markets Fund
(Class S Shares/HEMSX)		 $75 1.55%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 75
Expense Ratio, Percent 1.55% [114]
Net Assets $ 32,000,000
Holdings Count | Holding 57
Investment Company Portfolio Turnover 28.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $32M
Number of portfolio holdings 57
Portfolio turnover rate 28%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 9.5
Tencent Holdings Ltd 4.5
Samsung Electronics Co Ltd 4.2
BYD Co Ltd 3.7
Full Truck Alliance Co (ADR) 3.7
Asset Allocation (% of net assets)
Common Stocks 97.4
Investment Companies 2.6
Private Placements 0.1
Other (0.1)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 9.5
Tencent Holdings Ltd 4.5
Samsung Electronics Co Ltd 4.2
BYD Co Ltd 3.7
Full Truck Alliance Co (ADR) 3.7
C000183881 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Emerging Markets Fund
Class Name Class T Shares
Trading Symbol HEMTX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Emerging Markets Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Emerging Markets Fund
(Class T Shares/HEMTX)		 $62 1.28%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 62
Expense Ratio, Percent 1.28% [115]
Net Assets $ 32,000,000
Holdings Count | Holding 57
Investment Company Portfolio Turnover 28.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $32M
Number of portfolio holdings 57
Portfolio turnover rate 28%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 9.5
Tencent Holdings Ltd 4.5
Samsung Electronics Co Ltd 4.2
BYD Co Ltd 3.7
Full Truck Alliance Co (ADR) 3.7
Asset Allocation (% of net assets)
Common Stocks 97.4
Investment Companies 2.6
Private Placements 0.1
Other (0.1)
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Taiwan Semiconductor Manufacturing Co Ltd 9.5
Tencent Holdings Ltd 4.5
Samsung Electronics Co Ltd 4.2
BYD Co Ltd 3.7
Full Truck Alliance Co (ADR) 3.7
C000183893 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Equity Income Fund
Class Name Class A Shares
Trading Symbol HFQAX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Equity Income Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Equity Income Fund
(Class A Shares/HFQAX)		 $58 1.15%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 58
Expense Ratio, Percent 1.15% [116]
Net Assets $ 5,826,000,000
Holdings Count | Holding 75
Investment Company Portfolio Turnover 63.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $5,826M
Number of portfolio holdings 75
Portfolio turnover rate 63%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Roche Holding AG 3.5
Imperial Brands PLC 3.2
British American Tobacco PLC 3.1
Sanofi 2.9
Unilever PLC 2.8
Asset Allocation (% of net assets)
Common Stocks 94.1
Investment Companies 2.2
Preferred Stocks 1.6
Other 2.1
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Roche Holding AG 3.5
Imperial Brands PLC 3.2
British American Tobacco PLC 3.1
Sanofi 2.9
Unilever PLC 2.8
C000183894 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Equity Income Fund
Class Name Class C Shares
Trading Symbol HFQCX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Equity Income Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Equity Income Fund
(Class C Shares/HFQCX)		 $87 1.71%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 87
Expense Ratio, Percent 1.71% [117]
Net Assets $ 5,826,000,000
Holdings Count | Holding 75
Investment Company Portfolio Turnover 63.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $5,826M
Number of portfolio holdings 75
Portfolio turnover rate 63%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Roche Holding AG 3.5
Imperial Brands PLC 3.2
British American Tobacco PLC 3.1
Sanofi 2.9
Unilever PLC 2.8
Asset Allocation (% of net assets)
Common Stocks 94.1
Investment Companies 2.2
Preferred Stocks 1.6
Other 2.1
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Roche Holding AG 3.5
Imperial Brands PLC 3.2
British American Tobacco PLC 3.1
Sanofi 2.9
Unilever PLC 2.8
C000183895 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Equity Income Fund
Class Name Class D Shares
Trading Symbol HFQDX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Equity Income Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/reports. You can also request this information by contacting us at 1-800-525-3713.
Additional Information Phone Number 1-800-525-3713
Additional Information Website janushenderson.com/reports
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Equity Income Fund
(Class D Shares/HFQDX)		 $43 0.85%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 43
Expense Ratio, Percent 0.85% [118]
Net Assets $ 5,826,000,000
Holdings Count | Holding 75
Investment Company Portfolio Turnover 63.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $5,826M
Number of portfolio holdings 75
Portfolio turnover rate 63%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Roche Holding AG 3.5
Imperial Brands PLC 3.2
British American Tobacco PLC 3.1
Sanofi 2.9
Unilever PLC 2.8
Asset Allocation (% of net assets)
Common Stocks 94.1
Investment Companies 2.2
Preferred Stocks 1.6
Other 2.1
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Roche Holding AG 3.5
Imperial Brands PLC 3.2
British American Tobacco PLC 3.1
Sanofi 2.9
Unilever PLC 2.8
C000183896 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Equity Income Fund
Class Name Class I Shares
Trading Symbol HFQIX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Equity Income Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Equity Income Fund
(Class I Shares/HFQIX)		 $40 0.79%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 40
Expense Ratio, Percent 0.79% [119]
Net Assets $ 5,826,000,000
Holdings Count | Holding 75
Investment Company Portfolio Turnover 63.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $5,826M
Number of portfolio holdings 75
Portfolio turnover rate 63%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Roche Holding AG 3.5
Imperial Brands PLC 3.2
British American Tobacco PLC 3.1
Sanofi 2.9
Unilever PLC 2.8
Asset Allocation (% of net assets)
Common Stocks 94.1
Investment Companies 2.2
Preferred Stocks 1.6
Other 2.1
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Roche Holding AG 3.5
Imperial Brands PLC 3.2
British American Tobacco PLC 3.1
Sanofi 2.9
Unilever PLC 2.8
C000183897 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Equity Income Fund
Class Name Class N Shares
Trading Symbol HFQRX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Equity Income Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Equity Income Fund
(Class N Shares/HFQRX)		 $35 0.69%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 35
Expense Ratio, Percent 0.69% [120]
Net Assets $ 5,826,000,000
Holdings Count | Holding 75
Investment Company Portfolio Turnover 63.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $5,826M
Number of portfolio holdings 75
Portfolio turnover rate 63%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Roche Holding AG 3.5
Imperial Brands PLC 3.2
British American Tobacco PLC 3.1
Sanofi 2.9
Unilever PLC 2.8
Asset Allocation (% of net assets)
Common Stocks 94.1
Investment Companies 2.2
Preferred Stocks 1.6
Other 2.1
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Roche Holding AG 3.5
Imperial Brands PLC 3.2
British American Tobacco PLC 3.1
Sanofi 2.9
Unilever PLC 2.8
C000183899 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Equity Income Fund
Class Name Class S Shares
Trading Symbol HFQSX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Equity Income Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Equity Income Fund
(Class S Shares/HFQSX)		 $61 1.20%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 61
Expense Ratio, Percent 1.20% [121]
Net Assets $ 5,826,000,000
Holdings Count | Holding 75
Investment Company Portfolio Turnover 63.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $5,826M
Number of portfolio holdings 75
Portfolio turnover rate 63%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Roche Holding AG 3.5
Imperial Brands PLC 3.2
British American Tobacco PLC 3.1
Sanofi 2.9
Unilever PLC 2.8
Asset Allocation (% of net assets)
Common Stocks 94.1
Investment Companies 2.2
Preferred Stocks 1.6
Other 2.1
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Roche Holding AG 3.5
Imperial Brands PLC 3.2
British American Tobacco PLC 3.1
Sanofi 2.9
Unilever PLC 2.8
C000183900 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Equity Income Fund
Class Name Class T Shares
Trading Symbol HFQTX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Equity Income Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Equity Income Fund
(Class T Shares/HFQTX)		 $47 0.93%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 47
Expense Ratio, Percent 0.93% [122]
Net Assets $ 5,826,000,000
Holdings Count | Holding 75
Investment Company Portfolio Turnover 63.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $5,826M
Number of portfolio holdings 75
Portfolio turnover rate 63%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Roche Holding AG 3.5
Imperial Brands PLC 3.2
British American Tobacco PLC 3.1
Sanofi 2.9
Unilever PLC 2.8
Asset Allocation (% of net assets)
Common Stocks 94.1
Investment Companies 2.2
Preferred Stocks 1.6
Other 2.1
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Roche Holding AG 3.5
Imperial Brands PLC 3.2
British American Tobacco PLC 3.1
Sanofi 2.9
Unilever PLC 2.8
C000183903 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson European Focus Fund
Class Name Class A Shares
Trading Symbol HFEAX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson European Focus Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson European Focus Fund
(Class A Shares/HFEAX)		 $65 1.30%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 65
Expense Ratio, Percent 1.30% [123]
Net Assets $ 530,000,000
Holdings Count | Holding 46
Investment Company Portfolio Turnover 71.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $530M
Number of portfolio holdings 46
Portfolio turnover rate 71%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Allianz SE (REG) 4.2
Novartis AG 4.1
RELX PLC 4.1
UniCredit SpA 3.9
Deutsche Telekom AG 3.8
Asset Allocation (% of net assets)
Common Stocks 97.8
Investment Companies 1.3
Other 0.9
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Allianz SE (REG) 4.2
Novartis AG 4.1
RELX PLC 4.1
UniCredit SpA 3.9
Deutsche Telekom AG 3.8
C000183904 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson European Focus Fund
Class Name Class C Shares
Trading Symbol HFECX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson European Focus Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson European Focus Fund
(Class C Shares/HFECX)		 $103 2.07%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 103
Expense Ratio, Percent 2.07% [124]
Net Assets $ 530,000,000
Holdings Count | Holding 46
Investment Company Portfolio Turnover 71.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $530M
Number of portfolio holdings 46
Portfolio turnover rate 71%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Allianz SE (REG) 4.2
Novartis AG 4.1
RELX PLC 4.1
UniCredit SpA 3.9
Deutsche Telekom AG 3.8
Asset Allocation (% of net assets)
Common Stocks 97.8
Investment Companies 1.3
Other 0.9
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Allianz SE (REG) 4.2
Novartis AG 4.1
RELX PLC 4.1
UniCredit SpA 3.9
Deutsche Telekom AG 3.8
C000183905 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson European Focus Fund
Class Name Class D Shares
Trading Symbol HFEDX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson European Focus Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/reports. You can also request this information by contacting us at 1-800-525-3713.
Additional Information Phone Number 1-800-525-3713
Additional Information Website janushenderson.com/reports
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson European Focus Fund
(Class D Shares/HFEDX)		 $55 1.09%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 55
Expense Ratio, Percent 1.09% [125]
Net Assets $ 530,000,000
Holdings Count | Holding 46
Investment Company Portfolio Turnover 71.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $530M
Number of portfolio holdings 46
Portfolio turnover rate 71%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Allianz SE (REG) 4.2
Novartis AG 4.1
RELX PLC 4.1
UniCredit SpA 3.9
Deutsche Telekom AG 3.8
Asset Allocation (% of net assets)
Common Stocks 97.8
Investment Companies 1.3
Other 0.9
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Allianz SE (REG) 4.2
Novartis AG 4.1
RELX PLC 4.1
UniCredit SpA 3.9
Deutsche Telekom AG 3.8
C000183906 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson European Focus Fund
Class Name Class I Shares
Trading Symbol HFEIX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson European Focus Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson European Focus Fund
(Class I Shares/HFEIX)		 $54 1.07%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 54
Expense Ratio, Percent 1.07% [126]
Net Assets $ 530,000,000
Holdings Count | Holding 46
Investment Company Portfolio Turnover 71.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $530M
Number of portfolio holdings 46
Portfolio turnover rate 71%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Allianz SE (REG) 4.2
Novartis AG 4.1
RELX PLC 4.1
UniCredit SpA 3.9
Deutsche Telekom AG 3.8
Asset Allocation (% of net assets)
Common Stocks 97.8
Investment Companies 1.3
Other 0.9
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Allianz SE (REG) 4.2
Novartis AG 4.1
RELX PLC 4.1
UniCredit SpA 3.9
Deutsche Telekom AG 3.8
C000183907 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson European Focus Fund
Class Name Class N Shares
Trading Symbol HFERX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson European Focus Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson European Focus Fund
(Class N Shares/HFERX)		 $48 0.96%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 48
Expense Ratio, Percent 0.96% [127]
Net Assets $ 530,000,000
Holdings Count | Holding 46
Investment Company Portfolio Turnover 71.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $530M
Number of portfolio holdings 46
Portfolio turnover rate 71%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Allianz SE (REG) 4.2
Novartis AG 4.1
RELX PLC 4.1
UniCredit SpA 3.9
Deutsche Telekom AG 3.8
Asset Allocation (% of net assets)
Common Stocks 97.8
Investment Companies 1.3
Other 0.9
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Allianz SE (REG) 4.2
Novartis AG 4.1
RELX PLC 4.1
UniCredit SpA 3.9
Deutsche Telekom AG 3.8
C000183909 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson European Focus Fund
Class Name Class S Shares
Trading Symbol HFESX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson European Focus Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson European Focus Fund
(Class S Shares/HFESX)		 $68 1.37%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 68
Expense Ratio, Percent 1.37% [128]
Net Assets $ 530,000,000
Holdings Count | Holding 46
Investment Company Portfolio Turnover 71.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $530M
Number of portfolio holdings 46
Portfolio turnover rate 71%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Allianz SE (REG) 4.2
Novartis AG 4.1
RELX PLC 4.1
UniCredit SpA 3.9
Deutsche Telekom AG 3.8
Asset Allocation (% of net assets)
Common Stocks 97.8
Investment Companies 1.3
Other 0.9
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Allianz SE (REG) 4.2
Novartis AG 4.1
RELX PLC 4.1
UniCredit SpA 3.9
Deutsche Telekom AG 3.8
C000183910 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson European Focus Fund
Class Name Class T Shares
Trading Symbol HFETX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson European Focus Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson European Focus Fund
(Class T Shares/HFETX)		 $61 1.21%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 61
Expense Ratio, Percent 1.21% [129]
Net Assets $ 530,000,000
Holdings Count | Holding 46
Investment Company Portfolio Turnover 71.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $530M
Number of portfolio holdings 46
Portfolio turnover rate 71%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Allianz SE (REG) 4.2
Novartis AG 4.1
RELX PLC 4.1
UniCredit SpA 3.9
Deutsche Telekom AG 3.8
Asset Allocation (% of net assets)
Common Stocks 97.8
Investment Companies 1.3
Other 0.9
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Allianz SE (REG) 4.2
Novartis AG 4.1
RELX PLC 4.1
UniCredit SpA 3.9
Deutsche Telekom AG 3.8
C000219909 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Sustainable Equity Fund
Class Name Class A Shares
Trading Symbol JEASX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Sustainable Equity Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Sustainable Equity Fund
(Class A Shares/JEASX)		 $60 1.23%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 60
Expense Ratio, Percent 1.23% [130]
Net Assets $ 33,000,000
Holdings Count | Holding 58
Investment Company Portfolio Turnover 15.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $33M
Number of portfolio holdings 58
Portfolio turnover rate 15%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 5.2
NVIDIA Corp 4.0
Progressive Corp/The 3.7
Spotify Technology SA 3.7
McKesson Corp 3.5
Asset Allocation (% of net assets)
Common Stocks 98.2
Investment Companies 1.7
Other 0.1
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 5.2
NVIDIA Corp 4.0
Progressive Corp/The 3.7
Spotify Technology SA 3.7
McKesson Corp 3.5
C000219911 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Sustainable Equity Fund
Class Name Class C Shares
Trading Symbol JECTX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Sustainable Equity Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Sustainable Equity Fund
(Class C Shares/JECTX)		 $65 1.34%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 65
Expense Ratio, Percent 1.34% [131]
Net Assets $ 33,000,000
Holdings Count | Holding 58
Investment Company Portfolio Turnover 15.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $33M
Number of portfolio holdings 58
Portfolio turnover rate 15%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 5.2
NVIDIA Corp 4.0
Progressive Corp/The 3.7
Spotify Technology SA 3.7
McKesson Corp 3.5
Asset Allocation (% of net assets)
Common Stocks 98.2
Investment Companies 1.7
Other 0.1
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 5.2
NVIDIA Corp 4.0
Progressive Corp/The 3.7
Spotify Technology SA 3.7
McKesson Corp 3.5
C000219910 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Sustainable Equity Fund
Class Name Class D Shares
Trading Symbol JEDTX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Sustainable Equity Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/reports. You can also request this information by contacting us at 1-800-525-3713.
Additional Information Phone Number 1-800-525-3713
Additional Information Website janushenderson.com/reports
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Sustainable Equity Fund
(Class D Shares/JEDTX)		 $48 0.99%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 48
Expense Ratio, Percent 0.99% [132]
Net Assets $ 33,000,000
Holdings Count | Holding 58
Investment Company Portfolio Turnover 15.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $33M
Number of portfolio holdings 58
Portfolio turnover rate 15%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 5.2
NVIDIA Corp 4.0
Progressive Corp/The 3.7
Spotify Technology SA 3.7
McKesson Corp 3.5
Asset Allocation (% of net assets)
Common Stocks 98.2
Investment Companies 1.7
Other 0.1
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 5.2
NVIDIA Corp 4.0
Progressive Corp/The 3.7
Spotify Technology SA 3.7
McKesson Corp 3.5
C000219912 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Sustainable Equity Fund
Class Name Class I Shares
Trading Symbol JEUIX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Sustainable Equity Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Sustainable Equity Fund
(Class I Shares/JEUIX)		 $48 0.99%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 48
Expense Ratio, Percent 0.99% [133]
Net Assets $ 33,000,000
Holdings Count | Holding 58
Investment Company Portfolio Turnover 15.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $33M
Number of portfolio holdings 58
Portfolio turnover rate 15%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 5.2
NVIDIA Corp 4.0
Progressive Corp/The 3.7
Spotify Technology SA 3.7
McKesson Corp 3.5
Asset Allocation (% of net assets)
Common Stocks 98.2
Investment Companies 1.7
Other 0.1
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 5.2
NVIDIA Corp 4.0
Progressive Corp/The 3.7
Spotify Technology SA 3.7
McKesson Corp 3.5
C000219908 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Sustainable Equity Fund
Class Name Class N Shares
Trading Symbol JETNX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Sustainable Equity Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Sustainable Equity Fund
(Class N Shares/JETNX)		 $42 0.86%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 42
Expense Ratio, Percent 0.86% [134]
Net Assets $ 33,000,000
Holdings Count | Holding 58
Investment Company Portfolio Turnover 15.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $33M
Number of portfolio holdings 58
Portfolio turnover rate 15%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 5.2
NVIDIA Corp 4.0
Progressive Corp/The 3.7
Spotify Technology SA 3.7
McKesson Corp 3.5
Asset Allocation (% of net assets)
Common Stocks 98.2
Investment Companies 1.7
Other 0.1
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 5.2
NVIDIA Corp 4.0
Progressive Corp/The 3.7
Spotify Technology SA 3.7
McKesson Corp 3.5
C000225293 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Sustainable Equity Fund
Class Name Class R Shares
Trading Symbol JEGRX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Sustainable Equity Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Sustainable Equity Fund
(Class R Shares/JEGRX)		 $54 1.11%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 54
Expense Ratio, Percent 1.11% [135]
Net Assets $ 33,000,000
Holdings Count | Holding 58
Investment Company Portfolio Turnover 15.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $33M
Number of portfolio holdings 58
Portfolio turnover rate 15%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 5.2
NVIDIA Corp 4.0
Progressive Corp/The 3.7
Spotify Technology SA 3.7
McKesson Corp 3.5
Asset Allocation (% of net assets)
Common Stocks 98.2
Investment Companies 1.7
Other 0.1
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 5.2
NVIDIA Corp 4.0
Progressive Corp/The 3.7
Spotify Technology SA 3.7
McKesson Corp 3.5
C000219906 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Sustainable Equity Fund
Class Name Class S Shares
Trading Symbol JESSX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Sustainable Equity Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Sustainable Equity Fund
(Class S Shares/JESSX)		 $48 0.98%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 48
Expense Ratio, Percent 0.98% [136]
Net Assets $ 33,000,000
Holdings Count | Holding 58
Investment Company Portfolio Turnover 15.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $33M
Number of portfolio holdings 58
Portfolio turnover rate 15%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 5.2
NVIDIA Corp 4.0
Progressive Corp/The 3.7
Spotify Technology SA 3.7
McKesson Corp 3.5
Asset Allocation (% of net assets)
Common Stocks 98.2
Investment Companies 1.7
Other 0.1
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 5.2
NVIDIA Corp 4.0
Progressive Corp/The 3.7
Spotify Technology SA 3.7
McKesson Corp 3.5
C000219907 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson Global Sustainable Equity Fund
Class Name Class T Shares
Trading Symbol JETTX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson Global Sustainable Equity Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson Global Sustainable Equity Fund
(Class T Shares/JETTX)		 $54 1.10%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 54
Expense Ratio, Percent 1.10% [137]
Net Assets $ 33,000,000
Holdings Count | Holding 58
Investment Company Portfolio Turnover 15.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $33M
Number of portfolio holdings 58
Portfolio turnover rate 15%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 5.2
NVIDIA Corp 4.0
Progressive Corp/The 3.7
Spotify Technology SA 3.7
McKesson Corp 3.5
Asset Allocation (% of net assets)
Common Stocks 98.2
Investment Companies 1.7
Other 0.1
Top 5 Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
Microsoft Corp 5.2
NVIDIA Corp 4.0
Progressive Corp/The 3.7
Spotify Technology SA 3.7
McKesson Corp 3.5
C000240132 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson U.S. Dividend Income Fund
Class Name Class D Shares
Trading Symbol JDDVX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson U.S. Dividend Income Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/reports. You can also request this information by contacting us at 1-800-525-3713.
Additional Information Phone Number 1-800-525-3713
Additional Information Website janushenderson.com/reports
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson U.S. Dividend Income Fund
(Class D Shares/JDDVX)		 $42 0.85%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 42
Expense Ratio, Percent 0.85% [138]
Net Assets $ 39,000,000
Holdings Count | Holding 60
Investment Company Portfolio Turnover 42.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $39M
Number of portfolio holdings 60
Portfolio turnover rate 42%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
JPMorgan Chase & Co 4.6
Chevron Corp 3.2
Johnson & Johnson 3.0
Morgan Stanley 3.0
Goldman Sachs Group Inc 2.6
Asset Allocation (% of net assets)
Common Stocks 99.4
Investment Companies 1.3
Other (0.7)
Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
JPMorgan Chase & Co 4.6
Chevron Corp 3.2
Johnson & Johnson 3.0
Morgan Stanley 3.0
Goldman Sachs Group Inc 2.6
C000240130 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson U.S. Dividend Income Fund
Class Name Class I Shares
Trading Symbol JIDVX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson U.S. Dividend Income Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson U.S. Dividend Income Fund
(Class I Shares/JIDVX)		 $39 0.78%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 39
Expense Ratio, Percent 0.78% [139]
Net Assets $ 39,000,000
Holdings Count | Holding 60
Investment Company Portfolio Turnover 42.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $39M
Number of portfolio holdings 60
Portfolio turnover rate 42%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
JPMorgan Chase & Co 4.6
Chevron Corp 3.2
Johnson & Johnson 3.0
Morgan Stanley 3.0
Goldman Sachs Group Inc 2.6
Asset Allocation (% of net assets)
Common Stocks 99.4
Investment Companies 1.3
Other (0.7)
Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
JPMorgan Chase & Co 4.6
Chevron Corp 3.2
Johnson & Johnson 3.0
Morgan Stanley 3.0
Goldman Sachs Group Inc 2.6
C000240131 [Member]  
Shareholder Report [Line Items]  
Fund Name Janus Henderson U.S. Dividend Income Fund
Class Name Class N Shares
Trading Symbol JNDVX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about the Janus Henderson U.S. Dividend Income Fund (the "Fund”) for the period of October 1, 2024 to March 31, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at janushenderson.com/info. You can also request this information by contacting us at 1-877-335-2687.
Additional Information Phone Number 1-877-335-2687
Additional Information Website janushenderson.com/info
Expenses [Text Block]
What were the costs for the last 6 months?
(Based on a hypothetical $10,000 investment)
Fund (Class) Cost of a
$10,000 investment		 Cost paid as a percentage
of a $10,000 investment
Janus Henderson U.S. Dividend Income Fund
(Class N Shares/JNDVX)		 $36 0.73%*
​*
Annualized for periods of less than one full year.
Expenses Paid, Amount $ 36
Expense Ratio, Percent 0.73% [140]
Net Assets $ 39,000,000
Holdings Count | Holding 60
Investment Company Portfolio Turnover 42.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Net assets $39M
Number of portfolio holdings 60
Portfolio turnover rate 42%
Holdings [Text Block]
What did the Fund invest in?
5 Largest Equity Holdings (% of net assets)
JPMorgan Chase & Co 4.6
Chevron Corp 3.2
Johnson & Johnson 3.0
Morgan Stanley 3.0
Goldman Sachs Group Inc 2.6
Asset Allocation (% of net assets)
Common Stocks 99.4
Investment Companies 1.3
Other (0.7)
Country Allocations (% of investments)
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
5 Largest Equity Holdings (% of net assets)
JPMorgan Chase & Co 4.6
Chevron Corp 3.2
Johnson & Johnson 3.0
Morgan Stanley 3.0
Goldman Sachs Group Inc 2.6
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[136] Annualized for periods of less than one full year.
[137] Annualized for periods of less than one full year.
[138] Annualized for periods of less than one full year.
[139] Annualized for periods of less than one full year.
[140] Annualized for periods of less than one full year.