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Shareholder Report
 12 Months Ended 24 Months Ended 44 Months Ended 75 Months Ended 79 Months Ended 103 Months Ended
Oct. 31, 2025
USD ($)
holding
Oct. 31, 2025
USD ($)
holding
Oct. 31, 2025
USD ($)
holding
Oct. 31, 2025
USD ($)
holding
Oct. 31, 2025
USD ($)
holding
Oct. 31, 2025
USD ($)
holding
Shareholder Report [Line Items]            
Document Type N-CSR          
Amendment Flag false          
Registrant Name AMERICAN CENTURY MUTUAL FUNDS, INC.          
Entity Central Index Key 0000100334          
Entity Investment Company Type N-1A          
Document Period End Date Oct. 31, 2025          
Shareholder Report Annual or Semi-Annual Annual Shareholder Report          
C000017045 [Member]            
Shareholder Report [Line Items]            
Fund Name Balanced Fund          
Class Name Investor Class          
Trading Symbol TWBIX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Balanced Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Investor Class$930.88%
          
Expenses Paid, Amount $ 93          
Expense Ratio, Percent 0.88%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Balanced Fund Investor Class returned 11.13% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth and current income by investing approximately 60% of its assets in equity securities and the remainder in bonds and other fixed-income securities.
•
In information technology, semiconductors and semiconductor equipment stocks hurt relative results. Several of the leading detractors are explained by their exposure to artificial intelligence (AI). A notable relative detractor was an underweight to AI chipmaker Advanced Micro Devices. It also hurt to have no expsoure to shares of AI software and consulting firm Palantir Technologies.
•
Positioning in the health care sector also detracted from performance. Health care provider and services giant UnitedHealth Group was the leading detractor in the sector. A stake in pharmaceuticals company Novo Nordisk, maker of popular weight-loss drug Ozempic, was another source of weakness.
•
Stock selection in the communication services sector contributed most to relative performance. It helped to avoid shares of poor-performing media companies. An overweight to internet search giant Alphabet, parent of Google and YouTube, was a leading contributor to relative results. The company's results benefited from AI-enhanced advertising placement and content creation.
•
The bond allocation produced positive results amid uncertainty around the health of the economy and job market. In those conditions, the Federal Reserve cut short-term interest rates four times during the period. In addition, it was beneficial to underweight Treasury bonds in favor of higher-yielding corporate and securitized debt.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
October 31, 2015 through October 31, 2025
3298534883338
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 Year10 Year
Investor Class11.13%8.13%7.81%
Regulatory Index
S&P 50021.45%17.64%14.64%
Bloomberg U.S. Aggregate Bond6.16%-0.24%1.90%
Performance Index
60% S&P 500/40% Bloomberg U.S. Aggregate Bond15.29%10.37%9.63%
          
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 917,046,478 $ 917,046,478 $ 917,046,478 $ 917,046,478 $ 917,046,478 $ 917,046,478
Holdings Count | holding 569 569 569 569 569 569
Advisory Fees Paid, Amount $ 7,742,067          
Investment Company, Portfolio Turnover 84.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Common Stocks60.3%
U.S. Government Agency Mortgage-Backed Securities11.3%
U.S. Treasury Securities9.1%
Corporate Bonds8.3%
Collateralized Mortgage Obligations4.5%
Asset-Backed Securities1.8%
Convertible Preferred Securities1.4%
Commercial Mortgage-Backed Securities0.8%
Collateralized Loan Obligations0.6%
U.S. Government Agency Securities0.5%
Preferred Securities0.5%
Municipal Securities0.3%
Exchange-Traded Funds0.2%
Sovereign Governments and Agencies0.1%
Short-Term Investments1.9%
Other Assets and Liabilities(1.6)%
          
C000017047 [Member]            
Shareholder Report [Line Items]            
Fund Name Balanced Fund          
Class Name I Class          
Trading Symbol ABINX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Balanced Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
I Class$720.68%
          
Expenses Paid, Amount $ 72          
Expense Ratio, Percent 0.68%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Balanced Fund I Class returned 11.34% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth and current income by investing approximately 60% of its assets in equity securities and the remainder in bonds and other fixed-income securities.
•
In information technology, semiconductors and semiconductor equipment stocks hurt relative results. Several of the leading detractors are explained by their exposure to artificial intelligence (AI). A notable relative detractor was an underweight to AI chipmaker Advanced Micro Devices. It also hurt to have no expsoure to shares of AI software and consulting firm Palantir Technologies.
•
Positioning in the health care sector also detracted from performance. Health care provider and services giant UnitedHealth Group was the leading detractor in the sector. A stake in pharmaceuticals company Novo Nordisk, maker of popular weight-loss drug Ozempic, was another source of weakness.
•
Stock selection in the communication services sector contributed most to relative performance. It helped to avoid shares of poor-performing media companies. An overweight to internet search giant Alphabet, parent of Google and YouTube, was a leading contributor to relative results. The company's results benefited from AI-enhanced advertising placement and content creation.
•
The bond allocation produced positive results amid uncertainty around the health of the economy and job market. In those conditions, the Federal Reserve cut short-term interest rates four times during the period. In addition, it was beneficial to underweight Treasury bonds in favor of higher-yielding corporate and securitized debt.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
October 31, 2015 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 Year10 Year
I Class11.34%8.35%8.03%
Regulatory Index
S&P 50021.45%17.64%14.64%
Bloomberg U.S. Aggregate Bond6.16%-0.24%1.90%
Performance Index
60% S&P 500/40% Bloomberg U.S. Aggregate Bond15.29%10.37%9.63%
          
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 917,046,478 $ 917,046,478 $ 917,046,478 $ 917,046,478 $ 917,046,478 $ 917,046,478
Holdings Count | holding 569 569 569 569 569 569
Advisory Fees Paid, Amount $ 7,742,067          
Investment Company, Portfolio Turnover 84.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Common Stocks60.3%
U.S. Government Agency Mortgage-Backed Securities11.3%
U.S. Treasury Securities9.1%
Corporate Bonds8.3%
Collateralized Mortgage Obligations4.5%
Asset-Backed Securities1.8%
Convertible Preferred Securities1.4%
Commercial Mortgage-Backed Securities0.8%
Collateralized Loan Obligations0.6%
U.S. Government Agency Securities0.5%
Preferred Securities0.5%
Municipal Securities0.3%
Exchange-Traded Funds0.2%
Sovereign Governments and Agencies0.1%
Short-Term Investments1.9%
Other Assets and Liabilities(1.6)%
          
C000189734 [Member]            
Shareholder Report [Line Items]            
Fund Name Balanced Fund          
Class Name R5 Class          
Trading Symbol ABGNX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Balanced Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
R5 Class$720.68%
          
Expenses Paid, Amount $ 72          
Expense Ratio, Percent 0.68%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Balanced Fund R5 Class returned 11.35% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth and current income by investing approximately 60% of its assets in equity securities and the remainder in bonds and other fixed-income securities.
•
In information technology, semiconductors and semiconductor equipment stocks hurt relative results. Several of the leading detractors are explained by their exposure to artificial intelligence (AI). A notable relative detractor was an underweight to AI chipmaker Advanced Micro Devices. It also hurt to have no expsoure to shares of AI software and consulting firm Palantir Technologies.
•
Positioning in the health care sector also detracted from performance. Health care provider and services giant UnitedHealth Group was the leading detractor in the sector. A stake in pharmaceuticals company Novo Nordisk, maker of popular weight-loss drug Ozempic, was another source of weakness.
•
Stock selection in the communication services sector contributed most to relative performance. It helped to avoid shares of poor-performing media companies. An overweight to internet search giant Alphabet, parent of Google and YouTube, was a leading contributor to relative results. The company's results benefited from AI-enhanced advertising placement and content creation.
•
The bond allocation produced positive results amid uncertainty around the health of the economy and job market. In those conditions, the Federal Reserve cut short-term interest rates four times during the period. In addition, it was beneficial to underweight Treasury bonds in favor of higher-yielding corporate and securitized debt.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
April 10, 2017 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 YearSince InceptionInception Date
R5 Class11.35%8.34%8.23%4/10/17
Regulatory Index
S&P 50021.45%17.64%15.16%—
Bloomberg U.S. Aggregate Bond6.16%-0.24%1.85%—
Performance Index
60% S&P 500/40% Bloomberg U.S. Aggregate Bond15.29%10.37%9.93%—
          
Performance Inception Date           Apr. 10, 2017
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 917,046,478 $ 917,046,478 $ 917,046,478 $ 917,046,478 $ 917,046,478 $ 917,046,478
Holdings Count | holding 569 569 569 569 569 569
Advisory Fees Paid, Amount $ 7,742,067          
Investment Company, Portfolio Turnover 84.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Common Stocks60.3%
U.S. Government Agency Mortgage-Backed Securities11.3%
U.S. Treasury Securities9.1%
Corporate Bonds8.3%
Collateralized Mortgage Obligations4.5%
Asset-Backed Securities1.8%
Convertible Preferred Securities1.4%
Commercial Mortgage-Backed Securities0.8%
Collateralized Loan Obligations0.6%
U.S. Government Agency Securities0.5%
Preferred Securities0.5%
Municipal Securities0.3%
Exchange-Traded Funds0.2%
Sovereign Governments and Agencies0.1%
Short-Term Investments1.9%
Other Assets and Liabilities(1.6)%
          
C000017101 [Member]            
Shareholder Report [Line Items]            
Fund Name Growth Fund          
Class Name Investor Class          
Trading Symbol TWCGX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Growth Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Investor Class$980.87%
          
Expenses Paid, Amount $ 98          
Expense Ratio, Percent 0.87%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Growth Fund Investor Class returned 25.81% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund’s performance compared to the Russell 1000 Growth Index.
•
The leading contributions to relative performance at the sector level came from positioning among materials, energy and real estate stocks. These sectors lagged in a market that was largely driven by enthusiasm for artificial intelligence (AI)-related stocks. We had little or no exposure to each of these sectors.
•
Among individual contributors, a notable source of strength was positioning among specific software stocks. For example, the leading contributor to relative results was a lack of exposure to digital publishing and marketing firm Adobe, whose business was perceived as being under threat from AI.
•
Positioning in the health care sector detracted most from performance. Pharmaceuticals company Novo Nordisk, maker of popular weight-loss drug Ozempic, and health care provider and services giant UnitedHealth Group were notable detractors in health care.
•
Stock selection in the consumer discretionary sector detracted from relative performance. Positioning among specialty retail and automobiles stocks hurt relative results in the sector the most. In general, specialty retail stocks suffered from weaker spending by lower-income and price-sensitive consumers. In automobiles, it detracted to be underweight in shares of Tesla.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
October 31, 2015 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 Year10 Year
Investor Class25.81%16.51%16.21%
Regulatory Index
Russell 100021.14%17.05%14.39%
Performance Index
Russell 1000 Growth30.52%19.24%18.28%
          
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 16,598,141,727 $ 16,598,141,727 $ 16,598,141,727 $ 16,598,141,727 $ 16,598,141,727 $ 16,598,141,727
Holdings Count | holding 77 77 77 77 77 77
Advisory Fees Paid, Amount $ 112,726,833          
Investment Company, Portfolio Turnover 38.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks99.8%Semiconductors and Semiconductor Equipment21%
Short-Term Investments0.2%Software20%
Other Assets and Liabilities0.0%Interactive Media and Services10%
 Technology Hardware, Storage and Peripherals9%
 Broadline Retail5%
          
C000017103 [Member]            
Shareholder Report [Line Items]            
Fund Name Growth Fund          
Class Name I Class          
Trading Symbol TWGIX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Growth Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
I Class$760.67%
          
Expenses Paid, Amount $ 76          
Expense Ratio, Percent 0.67%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Growth Fund I Class returned 26.07% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund’s performance compared to the Russell 1000 Growth Index.
•
The leading contributions to relative performance at the sector level came from positioning among materials, energy and real estate stocks. These sectors lagged in a market that was largely driven by enthusiasm for artificial intelligence (AI)-related stocks. We had little or no exposure to each of these sectors.
•
Among individual contributors, a notable source of strength was positioning among specific software stocks. For example, the leading contributor to relative results was a lack of exposure to digital publishing and marketing firm Adobe, whose business was perceived as being under threat from AI.
•
Positioning in the health care sector detracted most from performance. Pharmaceuticals company Novo Nordisk, maker of popular weight-loss drug Ozempic, and health care provider and services giant UnitedHealth Group were notable detractors in health care.
•
Stock selection in the consumer discretionary sector detracted from relative performance. Positioning among specialty retail and automobiles stocks hurt relative results in the sector the most. In general, specialty retail stocks suffered from weaker spending by lower-income and price-sensitive consumers. In automobiles, it detracted to be underweight in shares of Tesla.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
October 31, 2015 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 Year10 Year
I Class26.07%16.74%16.44%
Regulatory Index
Russell 100021.14%17.05%14.39%
Performance Index
Russell 1000 Growth30.52%19.24%18.28%
          
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 16,598,141,727 $ 16,598,141,727 $ 16,598,141,727 $ 16,598,141,727 $ 16,598,141,727 $ 16,598,141,727
Holdings Count | holding 77 77 77 77 77 77
Advisory Fees Paid, Amount $ 112,726,833          
Investment Company, Portfolio Turnover 38.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks99.8%Semiconductors and Semiconductor Equipment21%
Short-Term Investments0.2%Software20%
Other Assets and Liabilities0.0%Interactive Media and Services10%
 Technology Hardware, Storage and Peripherals9%
 Broadline Retail5%
          
C000189744 [Member]            
Shareholder Report [Line Items]            
Fund Name Growth Fund          
Class Name Y Class          
Trading Symbol AGYWX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Growth Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Y Class$590.52%
          
Expenses Paid, Amount $ 59          
Expense Ratio, Percent 0.52%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Growth Fund Y Class returned 26.25% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund’s performance compared to the Russell 1000 Growth Index.
•
The leading contributions to relative performance at the sector level came from positioning among materials, energy and real estate stocks. These sectors lagged in a market that was largely driven by enthusiasm for artificial intelligence (AI)-related stocks. We had little or no exposure to each of these sectors.
•
Among individual contributors, a notable source of strength was positioning among specific software stocks. For example, the leading contributor to relative results was a lack of exposure to digital publishing and marketing firm Adobe, whose business was perceived as being under threat from AI.
•
Positioning in the health care sector detracted most from performance. Pharmaceuticals company Novo Nordisk, maker of popular weight-loss drug Ozempic, and health care provider and services giant UnitedHealth Group were notable detractors in health care.
•
Stock selection in the consumer discretionary sector detracted from relative performance. Positioning among specialty retail and automobiles stocks hurt relative results in the sector the most. In general, specialty retail stocks suffered from weaker spending by lower-income and price-sensitive consumers. In automobiles, it detracted to be underweight in shares of Tesla.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
April 10, 2017 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 YearSince InceptionInception Date
Y Class26.25%16.91%17.98%4/10/17
Regulatory Index
Russell 100021.14%17.05%14.89%—
Performance Index
Russell 1000 Growth30.52%19.24%19.68%—
          
Performance Inception Date           Apr. 10, 2017
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 16,598,141,727 $ 16,598,141,727 $ 16,598,141,727 $ 16,598,141,727 $ 16,598,141,727 $ 16,598,141,727
Holdings Count | holding 77 77 77 77 77 77
Advisory Fees Paid, Amount $ 112,726,833          
Investment Company, Portfolio Turnover 38.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks99.8%Semiconductors and Semiconductor Equipment21%
Short-Term Investments0.2%Software20%
Other Assets and Liabilities0.0%Interactive Media and Services10%
 Technology Hardware, Storage and Peripherals9%
 Broadline Retail5%
          
C000017102 [Member]            
Shareholder Report [Line Items]            
Fund Name Growth Fund          
Class Name A Class          
Trading Symbol TCRAX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Growth Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
A Class$1261.12%
          
Expenses Paid, Amount $ 126          
Expense Ratio, Percent 1.12%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Growth Fund A Class returned 25.50% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund’s performance compared to the Russell 1000 Growth Index.
•
The leading contributions to relative performance at the sector level came from positioning among materials, energy and real estate stocks. These sectors lagged in a market that was largely driven by enthusiasm for artificial intelligence (AI)-related stocks. We had little or no exposure to each of these sectors.
•
Among individual contributors, a notable source of strength was positioning among specific software stocks. For example, the leading contributor to relative results was a lack of exposure to digital publishing and marketing firm Adobe, whose business was perceived as being under threat from AI.
•
Positioning in the health care sector detracted most from performance. Pharmaceuticals company Novo Nordisk, maker of popular weight-loss drug Ozempic, and health care provider and services giant UnitedHealth Group were notable detractors in health care.
•
Stock selection in the consumer discretionary sector detracted from relative performance. Positioning among specialty retail and automobiles stocks hurt relative results in the sector the most. In general, specialty retail stocks suffered from weaker spending by lower-income and price-sensitive consumers. In automobiles, it detracted to be underweight in shares of Tesla.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
October 31, 2015 through October 31, 2025
The initial investment is adjusted to reflect the maximum initial sales charge.
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 Year10 Year
A Class25.50%16.22%15.92%
A Class - with sales charge18.29%14.85%15.24%
Regulatory Index
Russell 100021.14%17.05%14.39%
Performance Index
Russell 1000 Growth30.52%19.24%18.28%
          
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 16,598,141,727 $ 16,598,141,727 $ 16,598,141,727 $ 16,598,141,727 $ 16,598,141,727 $ 16,598,141,727
Holdings Count | holding 77 77 77 77 77 77
Advisory Fees Paid, Amount $ 112,726,833          
Investment Company, Portfolio Turnover 38.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks99.8%Semiconductors and Semiconductor Equipment21%
Short-Term Investments0.2%Software20%
Other Assets and Liabilities0.0%Interactive Media and Services10%
 Technology Hardware, Storage and Peripherals9%
 Broadline Retail5%
          
C000088050 [Member]            
Shareholder Report [Line Items]            
Fund Name Growth Fund          
Class Name C Class          
Trading Symbol TWRCX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Growth Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
C Class$2101.87%
          
Expenses Paid, Amount $ 210          
Expense Ratio, Percent 1.87%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Growth Fund C Class returned 24.57% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund’s performance compared to the Russell 1000 Growth Index.
•
The leading contributions to relative performance at the sector level came from positioning among materials, energy and real estate stocks. These sectors lagged in a market that was largely driven by enthusiasm for artificial intelligence (AI)-related stocks. We had little or no exposure to each of these sectors.
•
Among individual contributors, a notable source of strength was positioning among specific software stocks. For example, the leading contributor to relative results was a lack of exposure to digital publishing and marketing firm Adobe, whose business was perceived as being under threat from AI.
•
Positioning in the health care sector detracted most from performance. Pharmaceuticals company Novo Nordisk, maker of popular weight-loss drug Ozempic, and health care provider and services giant UnitedHealth Group were notable detractors in health care.
•
Stock selection in the consumer discretionary sector detracted from relative performance. Positioning among specialty retail and automobiles stocks hurt relative results in the sector the most. In general, specialty retail stocks suffered from weaker spending by lower-income and price-sensitive consumers. In automobiles, it detracted to be underweight in shares of Tesla.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
October 31, 2015 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 Year10 Year
C Class24.57%15.35%15.06%
Regulatory Index
Russell 100021.14%17.05%14.39%
Performance Index
Russell 1000 Growth30.52%19.24%18.28%
          
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 16,598,141,727 $ 16,598,141,727 $ 16,598,141,727 $ 16,598,141,727 $ 16,598,141,727 $ 16,598,141,727
Holdings Count | holding 77 77 77 77 77 77
Advisory Fees Paid, Amount $ 112,726,833          
Investment Company, Portfolio Turnover 38.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks99.8%Semiconductors and Semiconductor Equipment21%
Short-Term Investments0.2%Software20%
Other Assets and Liabilities0.0%Interactive Media and Services10%
 Technology Hardware, Storage and Peripherals9%
 Broadline Retail5%
          
C000017105 [Member]            
Shareholder Report [Line Items]            
Fund Name Growth Fund          
Class Name R Class          
Trading Symbol AGWRX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Growth Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
R Class$1541.37%
          
Expenses Paid, Amount $ 154          
Expense Ratio, Percent 1.37%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Growth Fund R Class returned 25.20% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund’s performance compared to the Russell 1000 Growth Index.
•
The leading contributions to relative performance at the sector level came from positioning among materials, energy and real estate stocks. These sectors lagged in a market that was largely driven by enthusiasm for artificial intelligence (AI)-related stocks. We had little or no exposure to each of these sectors.
•
Among individual contributors, a notable source of strength was positioning among specific software stocks. For example, the leading contributor to relative results was a lack of exposure to digital publishing and marketing firm Adobe, whose business was perceived as being under threat from AI.
•
Positioning in the health care sector detracted most from performance. Pharmaceuticals company Novo Nordisk, maker of popular weight-loss drug Ozempic, and health care provider and services giant UnitedHealth Group were notable detractors in health care.
•
Stock selection in the consumer discretionary sector detracted from relative performance. Positioning among specialty retail and automobiles stocks hurt relative results in the sector the most. In general, specialty retail stocks suffered from weaker spending by lower-income and price-sensitive consumers. In automobiles, it detracted to be underweight in shares of Tesla.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
October 31, 2015 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 Year10 Year
R Class25.20%15.93%15.63%
Regulatory Index
Russell 100021.14%17.05%14.39%
Performance Index
Russell 1000 Growth30.52%19.24%18.28%
          
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 16,598,141,727 $ 16,598,141,727 $ 16,598,141,727 $ 16,598,141,727 $ 16,598,141,727 $ 16,598,141,727
Holdings Count | holding 77 77 77 77 77 77
Advisory Fees Paid, Amount $ 112,726,833          
Investment Company, Portfolio Turnover 38.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks99.8%Semiconductors and Semiconductor Equipment21%
Short-Term Investments0.2%Software20%
Other Assets and Liabilities0.0%Interactive Media and Services10%
 Technology Hardware, Storage and Peripherals9%
 Broadline Retail5%
          
C000189743 [Member]            
Shareholder Report [Line Items]            
Fund Name Growth Fund          
Class Name R5 Class          
Trading Symbol AGWUX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Growth Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
R5 Class$760.67%
          
Expenses Paid, Amount $ 76          
Expense Ratio, Percent 0.67%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Growth Fund R5 Class returned 26.07% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund’s performance compared to the Russell 1000 Growth Index.
•
The leading contributions to relative performance at the sector level came from positioning among materials, energy and real estate stocks. These sectors lagged in a market that was largely driven by enthusiasm for artificial intelligence (AI)-related stocks. We had little or no exposure to each of these sectors.
•
Among individual contributors, a notable source of strength was positioning among specific software stocks. For example, the leading contributor to relative results was a lack of exposure to digital publishing and marketing firm Adobe, whose business was perceived as being under threat from AI.
•
Positioning in the health care sector detracted most from performance. Pharmaceuticals company Novo Nordisk, maker of popular weight-loss drug Ozempic, and health care provider and services giant UnitedHealth Group were notable detractors in health care.
•
Stock selection in the consumer discretionary sector detracted from relative performance. Positioning among specialty retail and automobiles stocks hurt relative results in the sector the most. In general, specialty retail stocks suffered from weaker spending by lower-income and price-sensitive consumers. In automobiles, it detracted to be underweight in shares of Tesla.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
April 10, 2017 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 YearSince InceptionInception Date
R5 Class26.07%16.74%17.81%4/10/17
Regulatory Index
Russell 100021.14%17.05%14.89%—
Performance Index
Russell 1000 Growth30.52%19.24%19.68%—
          
Performance Inception Date           Apr. 10, 2017
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 16,598,141,727 $ 16,598,141,727 $ 16,598,141,727 $ 16,598,141,727 $ 16,598,141,727 $ 16,598,141,727
Holdings Count | holding 77 77 77 77 77 77
Advisory Fees Paid, Amount $ 112,726,833          
Investment Company, Portfolio Turnover 38.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks99.8%Semiconductors and Semiconductor Equipment21%
Short-Term Investments0.2%Software20%
Other Assets and Liabilities0.0%Interactive Media and Services10%
 Technology Hardware, Storage and Peripherals9%
 Broadline Retail5%
          
C000131599 [Member]            
Shareholder Report [Line Items]            
Fund Name Growth Fund          
Class Name R6 Class          
Trading Symbol AGRDX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Growth Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
R6 Class$590.52%
          
Expenses Paid, Amount $ 59          
Expense Ratio, Percent 0.52%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Growth Fund R6 Class returned 26.25% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund’s performance compared to the Russell 1000 Growth Index.
•
The leading contributions to relative performance at the sector level came from positioning among materials, energy and real estate stocks. These sectors lagged in a market that was largely driven by enthusiasm for artificial intelligence (AI)-related stocks. We had little or no exposure to each of these sectors.
•
Among individual contributors, a notable source of strength was positioning among specific software stocks. For example, the leading contributor to relative results was a lack of exposure to digital publishing and marketing firm Adobe, whose business was perceived as being under threat from AI.
•
Positioning in the health care sector detracted most from performance. Pharmaceuticals company Novo Nordisk, maker of popular weight-loss drug Ozempic, and health care provider and services giant UnitedHealth Group were notable detractors in health care.
•
Stock selection in the consumer discretionary sector detracted from relative performance. Positioning among specialty retail and automobiles stocks hurt relative results in the sector the most. In general, specialty retail stocks suffered from weaker spending by lower-income and price-sensitive consumers. In automobiles, it detracted to be underweight in shares of Tesla.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
October 31, 2015 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 Year10 Year
R6 Class26.25%16.91%16.62%
Regulatory Index
Russell 100021.14%17.05%14.39%
Performance Index
Russell 1000 Growth30.52%19.24%18.28%
          
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 16,598,141,727 $ 16,598,141,727 $ 16,598,141,727 $ 16,598,141,727 $ 16,598,141,727 $ 16,598,141,727
Holdings Count | holding 77 77 77 77 77 77
Advisory Fees Paid, Amount $ 112,726,833          
Investment Company, Portfolio Turnover 38.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks99.8%Semiconductors and Semiconductor Equipment21%
Short-Term Investments0.2%Software20%
Other Assets and Liabilities0.0%Interactive Media and Services10%
 Technology Hardware, Storage and Peripherals9%
 Broadline Retail5%
          
C000236113 [Member]            
Shareholder Report [Line Items]            
Fund Name Growth Fund          
Class Name G Class          
Trading Symbol ACIHX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Growth Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
G Class$00.00%
          
Expenses Paid, Amount $ 0          
Expense Ratio, Percent 0.00%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Growth Fund G Class returned 26.90% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund’s performance compared to the Russell 1000 Growth Index.
•
The leading contributions to relative performance at the sector level came from positioning among materials, energy and real estate stocks. These sectors lagged in a market that was largely driven by enthusiasm for artificial intelligence (AI)-related stocks. We had little or no exposure to each of these sectors.
•
Among individual contributors, a notable source of strength was positioning among specific software stocks. For example, the leading contributor to relative results was a lack of exposure to digital publishing and marketing firm Adobe, whose business was perceived as being under threat from AI.
•
Positioning in the health care sector detracted most from performance. Pharmaceuticals company Novo Nordisk, maker of popular weight-loss drug Ozempic, and health care provider and services giant UnitedHealth Group were notable detractors in health care.
•
Stock selection in the consumer discretionary sector detracted from relative performance. Positioning among specialty retail and automobiles stocks hurt relative results in the sector the most. In general, specialty retail stocks suffered from weaker spending by lower-income and price-sensitive consumers. In automobiles, it detracted to be underweight in shares of Tesla.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
March 1, 2022 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 YearSince InceptionInception Date
G Class26.90%16.78%3/1/22
Regulatory Index
Russell 100021.14%14.63%—
Performance Index
Russell 1000 Growth30.52%19.10%—
          
Performance Inception Date     Mar. 01, 2022      
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 16,598,141,727 $ 16,598,141,727 $ 16,598,141,727 $ 16,598,141,727 $ 16,598,141,727 $ 16,598,141,727
Holdings Count | holding 77 77 77 77 77 77
Advisory Fees Paid, Amount $ 112,726,833          
Investment Company, Portfolio Turnover 38.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks99.8%Semiconductors and Semiconductor Equipment21%
Short-Term Investments0.2%Software20%
Other Assets and Liabilities0.0%Interactive Media and Services10%
 Technology Hardware, Storage and Peripherals9%
 Broadline Retail5%
          
C000017106 [Member]            
Shareholder Report [Line Items]            
Fund Name Heritage Fund          
Class Name Investor Class          
Trading Symbol TWHIX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Heritage Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Investor Class$1091.00%
          
Expenses Paid, Amount $ 109          
Expense Ratio, Percent 1.00%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Heritage Fund Investor Class returned 17.77% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund's performance compared to the Russell Midcap Growth Index.
•
Information technology stocks contributed most to performance thanks to selection and allocation decisions, particularly among IT services and communications equipment stocks. Exposure to artificial intelligence (AI) strongly influenced performance. Communication networking firm Ciena was the leading contributor as a result of benefiting from exposure to AI infrastructure spending.
•
Positioning in the industrials sector contributed, led by building products and professional services firms. A notable source of strength was a stake in commercial building solutions company Johnson Controls International. It benefited from strong demand for its energy-efficiency and cooling solutions, particularly as they relate to the ongoing AI-related data center build-out.
•
Communication services stocks were the leading detractors as a result of stock choices and an underweight allocation. A relative lack of exposure to strong-performing entertainment stocks hurt relative results. Stock choices among interactive media and services companies also detracted from performance.
•
Stock selection meant the health care sector was another notable detractor. Companies in the life sciences tools and services industry underperformed. They were hurt by worries about the level of drug research spending amid heightened economic, political and regulatory uncertainty.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
October 31, 2015 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 Year10 Year
Investor Class17.77%10.06%11.58%
Regulatory Index
Russell 300020.81%16.74%14.08%
Performance Index
Russell Midcap Growth19.59%11.17%12.65%
          
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 6,125,756,314 $ 6,125,756,314 $ 6,125,756,314 $ 6,125,756,314 $ 6,125,756,314 $ 6,125,756,314
Holdings Count | holding 82 82 82 82 82 82
Advisory Fees Paid, Amount $ 50,265,902          
Investment Company, Portfolio Turnover 62.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks99.1%Software11%
Short-Term Investments0.9%Hotels, Restaurants and Leisure10%
Other Assets and Liabilities0.0%Aerospace and Defense7%
 Health Care Equipment and Supplies5%
 Biotechnology5%
          
C000017108 [Member]            
Shareholder Report [Line Items]            
Fund Name Heritage Fund          
Class Name I Class          
Trading Symbol ATHIX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Heritage Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
I Class$870.80%
          
Expenses Paid, Amount $ 87          
Expense Ratio, Percent 0.80%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Heritage Fund I Class returned 18.02% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund's performance compared to the Russell Midcap Growth Index.
•
Information technology stocks contributed most to performance thanks to selection and allocation decisions, particularly among IT services and communications equipment stocks. Exposure to artificial intelligence (AI) strongly influenced performance. Communication networking firm Ciena was the leading contributor as a result of benefiting from exposure to AI infrastructure spending.
•
Positioning in the industrials sector contributed, led by building products and professional services firms. A notable source of strength was a stake in commercial building solutions company Johnson Controls International. It benefited from strong demand for its energy-efficiency and cooling solutions, particularly as they relate to the ongoing AI-related data center build-out.
•
Communication services stocks were the leading detractors as a result of stock choices and an underweight allocation. A relative lack of exposure to strong-performing entertainment stocks hurt relative results. Stock choices among interactive media and services companies also detracted from performance.
•
Stock selection meant the health care sector was another notable detractor. Companies in the life sciences tools and services industry underperformed. They were hurt by worries about the level of drug research spending amid heightened economic, political and regulatory uncertainty.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
October 31, 2015 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 Year10 Year
I Class18.02%10.27%11.80%
Regulatory Index
Russell 300020.81%16.74%14.08%
Performance Index
Russell Midcap Growth19.59%11.17%12.65%
          
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 6,125,756,314 $ 6,125,756,314 $ 6,125,756,314 $ 6,125,756,314 $ 6,125,756,314 $ 6,125,756,314
Holdings Count | holding 82 82 82 82 82 82
Advisory Fees Paid, Amount $ 50,265,902          
Investment Company, Portfolio Turnover 62.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks99.1%Software11%
Short-Term Investments0.9%Hotels, Restaurants and Leisure10%
Other Assets and Liabilities0.0%Aerospace and Defense7%
 Health Care Equipment and Supplies5%
 Biotechnology5%
          
C000189746 [Member]            
Shareholder Report [Line Items]            
Fund Name Heritage Fund          
Class Name Y Class          
Trading Symbol ATHYX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Heritage Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Y Class$710.65%
          
Expenses Paid, Amount $ 71          
Expense Ratio, Percent 0.65%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Heritage Fund Y Class returned 18.19% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund's performance compared to the Russell Midcap Growth Index.
•
Information technology stocks contributed most to performance thanks to selection and allocation decisions, particularly among IT services and communications equipment stocks. Exposure to artificial intelligence (AI) strongly influenced performance. Communication networking firm Ciena was the leading contributor as a result of benefiting from exposure to AI infrastructure spending.
•
Positioning in the industrials sector contributed, led by building products and professional services firms. A notable source of strength was a stake in commercial building solutions company Johnson Controls International. It benefited from strong demand for its energy-efficiency and cooling solutions, particularly as they relate to the ongoing AI-related data center build-out.
•
Communication services stocks were the leading detractors as a result of stock choices and an underweight allocation. A relative lack of exposure to strong-performing entertainment stocks hurt relative results. Stock choices among interactive media and services companies also detracted from performance.
•
Stock selection meant the health care sector was another notable detractor. Companies in the life sciences tools and services industry underperformed. They were hurt by worries about the level of drug research spending amid heightened economic, political and regulatory uncertainty.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
April 10, 2017 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 YearSince InceptionInception Date
Y Class18.19%10.44%13.12%4/10/17
Regulatory Index
Russell 300020.81%16.74%14.50%—
Performance Index
Russell Midcap Growth19.59%11.17%13.48%—
          
Performance Inception Date           Apr. 10, 2017
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 6,125,756,314 $ 6,125,756,314 $ 6,125,756,314 $ 6,125,756,314 $ 6,125,756,314 $ 6,125,756,314
Holdings Count | holding 82 82 82 82 82 82
Advisory Fees Paid, Amount $ 50,265,902          
Investment Company, Portfolio Turnover 62.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks99.1%Software11%
Short-Term Investments0.9%Hotels, Restaurants and Leisure10%
Other Assets and Liabilities0.0%Aerospace and Defense7%
 Health Care Equipment and Supplies5%
 Biotechnology5%
          
C000017107 [Member]            
Shareholder Report [Line Items]            
Fund Name Heritage Fund          
Class Name A Class          
Trading Symbol ATHAX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Heritage Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
A Class$1361.25%
          
Expenses Paid, Amount $ 136          
Expense Ratio, Percent 1.25%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Heritage Fund A Class returned 17.52% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund's performance compared to the Russell Midcap Growth Index.
•
Information technology stocks contributed most to performance thanks to selection and allocation decisions, particularly among IT services and communications equipment stocks. Exposure to artificial intelligence (AI) strongly influenced performance. Communication networking firm Ciena was the leading contributor as a result of benefiting from exposure to AI infrastructure spending.
•
Positioning in the industrials sector contributed, led by building products and professional services firms. A notable source of strength was a stake in commercial building solutions company Johnson Controls International. It benefited from strong demand for its energy-efficiency and cooling solutions, particularly as they relate to the ongoing AI-related data center build-out.
•
Communication services stocks were the leading detractors as a result of stock choices and an underweight allocation. A relative lack of exposure to strong-performing entertainment stocks hurt relative results. Stock choices among interactive media and services companies also detracted from performance.
•
Stock selection meant the health care sector was another notable detractor. Companies in the life sciences tools and services industry underperformed. They were hurt by worries about the level of drug research spending amid heightened economic, political and regulatory uncertainty.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
October 31, 2015 through October 31, 2025
The initial investment is adjusted to reflect the maximum initial sales charge.
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 Year10 Year
A Class17.52%9.78%11.30%
A Class - with sales charge10.76%8.48%10.65%
Regulatory Index
Russell 300020.81%16.74%14.08%
Performance Index
Russell Midcap Growth19.59%11.17%12.65%
          
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 6,125,756,314 $ 6,125,756,314 $ 6,125,756,314 $ 6,125,756,314 $ 6,125,756,314 $ 6,125,756,314
Holdings Count | holding 82 82 82 82 82 82
Advisory Fees Paid, Amount $ 50,265,902          
Investment Company, Portfolio Turnover 62.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks99.1%Software11%
Short-Term Investments0.9%Hotels, Restaurants and Leisure10%
Other Assets and Liabilities0.0%Aerospace and Defense7%
 Health Care Equipment and Supplies5%
 Biotechnology5%
          
C000017109 [Member]            
Shareholder Report [Line Items]            
Fund Name Heritage Fund          
Class Name C Class          
Trading Symbol AHGCX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Heritage Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
C Class$2172.00%
          
Expenses Paid, Amount $ 217          
Expense Ratio, Percent 2.00%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Heritage Fund C Class returned 16.56% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund's performance compared to the Russell Midcap Growth Index.
•
Information technology stocks contributed most to performance thanks to selection and allocation decisions, particularly among IT services and communications equipment stocks. Exposure to artificial intelligence (AI) strongly influenced performance. Communication networking firm Ciena was the leading contributor as a result of benefiting from exposure to AI infrastructure spending.
•
Positioning in the industrials sector contributed, led by building products and professional services firms. A notable source of strength was a stake in commercial building solutions company Johnson Controls International. It benefited from strong demand for its energy-efficiency and cooling solutions, particularly as they relate to the ongoing AI-related data center build-out.
•
Communication services stocks were the leading detractors as a result of stock choices and an underweight allocation. A relative lack of exposure to strong-performing entertainment stocks hurt relative results. Stock choices among interactive media and services companies also detracted from performance.
•
Stock selection meant the health care sector was another notable detractor. Companies in the life sciences tools and services industry underperformed. They were hurt by worries about the level of drug research spending amid heightened economic, political and regulatory uncertainty.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
October 31, 2015 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 Year10 Year
C Class16.56%8.95%10.47%
Regulatory Index
Russell 300020.81%16.74%14.08%
Performance Index
Russell Midcap Growth19.59%11.17%12.65%
          
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 6,125,756,314 $ 6,125,756,314 $ 6,125,756,314 $ 6,125,756,314 $ 6,125,756,314 $ 6,125,756,314
Holdings Count | holding 82 82 82 82 82 82
Advisory Fees Paid, Amount $ 50,265,902          
Investment Company, Portfolio Turnover 62.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks99.1%Software11%
Short-Term Investments0.9%Hotels, Restaurants and Leisure10%
Other Assets and Liabilities0.0%Aerospace and Defense7%
 Health Care Equipment and Supplies5%
 Biotechnology5%
          
C000055524 [Member]            
Shareholder Report [Line Items]            
Fund Name Heritage Fund          
Class Name R Class          
Trading Symbol ATHWX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Heritage Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
R Class$1631.50%
          
Expenses Paid, Amount $ 163          
Expense Ratio, Percent 1.50%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Heritage Fund R Class returned 17.21% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund's performance compared to the Russell Midcap Growth Index.
•
Information technology stocks contributed most to performance thanks to selection and allocation decisions, particularly among IT services and communications equipment stocks. Exposure to artificial intelligence (AI) strongly influenced performance. Communication networking firm Ciena was the leading contributor as a result of benefiting from exposure to AI infrastructure spending.
•
Positioning in the industrials sector contributed, led by building products and professional services firms. A notable source of strength was a stake in commercial building solutions company Johnson Controls International. It benefited from strong demand for its energy-efficiency and cooling solutions, particularly as they relate to the ongoing AI-related data center build-out.
•
Communication services stocks were the leading detractors as a result of stock choices and an underweight allocation. A relative lack of exposure to strong-performing entertainment stocks hurt relative results. Stock choices among interactive media and services companies also detracted from performance.
•
Stock selection meant the health care sector was another notable detractor. Companies in the life sciences tools and services industry underperformed. They were hurt by worries about the level of drug research spending amid heightened economic, political and regulatory uncertainty.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
October 31, 2015 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 Year10 Year
R Class17.21%9.50%11.03%
Regulatory Index
Russell 300020.81%16.74%14.08%
Performance Index
Russell Midcap Growth19.59%11.17%12.65%
          
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 6,125,756,314 $ 6,125,756,314 $ 6,125,756,314 $ 6,125,756,314 $ 6,125,756,314 $ 6,125,756,314
Holdings Count | holding 82 82 82 82 82 82
Advisory Fees Paid, Amount $ 50,265,902          
Investment Company, Portfolio Turnover 62.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks99.1%Software11%
Short-Term Investments0.9%Hotels, Restaurants and Leisure10%
Other Assets and Liabilities0.0%Aerospace and Defense7%
 Health Care Equipment and Supplies5%
 Biotechnology5%
          
C000189745 [Member]            
Shareholder Report [Line Items]            
Fund Name Heritage Fund          
Class Name R5 Class          
Trading Symbol ATHGX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Heritage Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
R5 Class$870.80%
          
Expenses Paid, Amount $ 87          
Expense Ratio, Percent 0.80%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Heritage Fund R5 Class returned 18.01% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund's performance compared to the Russell Midcap Growth Index.
•
Information technology stocks contributed most to performance thanks to selection and allocation decisions, particularly among IT services and communications equipment stocks. Exposure to artificial intelligence (AI) strongly influenced performance. Communication networking firm Ciena was the leading contributor as a result of benefiting from exposure to AI infrastructure spending.
•
Positioning in the industrials sector contributed, led by building products and professional services firms. A notable source of strength was a stake in commercial building solutions company Johnson Controls International. It benefited from strong demand for its energy-efficiency and cooling solutions, particularly as they relate to the ongoing AI-related data center build-out.
•
Communication services stocks were the leading detractors as a result of stock choices and an underweight allocation. A relative lack of exposure to strong-performing entertainment stocks hurt relative results. Stock choices among interactive media and services companies also detracted from performance.
•
Stock selection meant the health care sector was another notable detractor. Companies in the life sciences tools and services industry underperformed. They were hurt by worries about the level of drug research spending amid heightened economic, political and regulatory uncertainty.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
April 10, 2017 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 YearSince InceptionInception Date
R5 Class18.01%10.27%12.95%4/10/17
Regulatory Index
Russell 300020.81%16.74%14.50%—
Performance Index
Russell Midcap Growth19.59%11.17%13.48%—
          
Performance Inception Date           Apr. 10, 2017
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 6,125,756,314 $ 6,125,756,314 $ 6,125,756,314 $ 6,125,756,314 $ 6,125,756,314 $ 6,125,756,314
Holdings Count | holding 82 82 82 82 82 82
Advisory Fees Paid, Amount $ 50,265,902          
Investment Company, Portfolio Turnover 62.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks99.1%Software11%
Short-Term Investments0.9%Hotels, Restaurants and Leisure10%
Other Assets and Liabilities0.0%Aerospace and Defense7%
 Health Care Equipment and Supplies5%
 Biotechnology5%
          
C000129042 [Member]            
Shareholder Report [Line Items]            
Fund Name Heritage Fund          
Class Name R6 Class          
Trading Symbol ATHDX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Heritage Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
R6 Class$710.65%
          
Expenses Paid, Amount $ 71          
Expense Ratio, Percent 0.65%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Heritage Fund R6 Class returned 18.19% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund's performance compared to the Russell Midcap Growth Index.
•
Information technology stocks contributed most to performance thanks to selection and allocation decisions, particularly among IT services and communications equipment stocks. Exposure to artificial intelligence (AI) strongly influenced performance. Communication networking firm Ciena was the leading contributor as a result of benefiting from exposure to AI infrastructure spending.
•
Positioning in the industrials sector contributed, led by building products and professional services firms. A notable source of strength was a stake in commercial building solutions company Johnson Controls International. It benefited from strong demand for its energy-efficiency and cooling solutions, particularly as they relate to the ongoing AI-related data center build-out.
•
Communication services stocks were the leading detractors as a result of stock choices and an underweight allocation. A relative lack of exposure to strong-performing entertainment stocks hurt relative results. Stock choices among interactive media and services companies also detracted from performance.
•
Stock selection meant the health care sector was another notable detractor. Companies in the life sciences tools and services industry underperformed. They were hurt by worries about the level of drug research spending amid heightened economic, political and regulatory uncertainty.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
October 31, 2015 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 Year10 Year
R6 Class18.19%10.44%11.98%
Regulatory Index
Russell 300020.81%16.74%14.08%
Performance Index
Russell Midcap Growth19.59%11.17%12.65%
          
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 6,125,756,314 $ 6,125,756,314 $ 6,125,756,314 $ 6,125,756,314 $ 6,125,756,314 $ 6,125,756,314
Holdings Count | holding 82 82 82 82 82 82
Advisory Fees Paid, Amount $ 50,265,902          
Investment Company, Portfolio Turnover 62.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks99.1%Software11%
Short-Term Investments0.9%Hotels, Restaurants and Leisure10%
Other Assets and Liabilities0.0%Aerospace and Defense7%
 Health Care Equipment and Supplies5%
 Biotechnology5%
          
C000236114 [Member]            
Shareholder Report [Line Items]            
Fund Name Heritage Fund          
Class Name G Class          
Trading Symbol ACILX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Heritage Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
G Class$00.00%
          
Expenses Paid, Amount $ 0          
Expense Ratio, Percent 0.00%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Heritage Fund G Class returned 18.98% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund's performance compared to the Russell Midcap Growth Index.
•
Information technology stocks contributed most to performance thanks to selection and allocation decisions, particularly among IT services and communications equipment stocks. Exposure to artificial intelligence (AI) strongly influenced performance. Communication networking firm Ciena was the leading contributor as a result of benefiting from exposure to AI infrastructure spending.
•
Positioning in the industrials sector contributed, led by building products and professional services firms. A notable source of strength was a stake in commercial building solutions company Johnson Controls International. It benefited from strong demand for its energy-efficiency and cooling solutions, particularly as they relate to the ongoing AI-related data center build-out.
•
Communication services stocks were the leading detractors as a result of stock choices and an underweight allocation. A relative lack of exposure to strong-performing entertainment stocks hurt relative results. Stock choices among interactive media and services companies also detracted from performance.
•
Stock selection meant the health care sector was another notable detractor. Companies in the life sciences tools and services industry underperformed. They were hurt by worries about the level of drug research spending amid heightened economic, political and regulatory uncertainty.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
March 1, 2022 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 YearSince InceptionInception Date
G Class18.98%11.52%3/1/22
Regulatory Index
Russell 300020.81%14.24%—
Performance Index
Russell Midcap Growth19.59%11.55%—
          
Performance Inception Date     Mar. 01, 2022      
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 6,125,756,314 $ 6,125,756,314 $ 6,125,756,314 $ 6,125,756,314 $ 6,125,756,314 $ 6,125,756,314
Holdings Count | holding 82 82 82 82 82 82
Advisory Fees Paid, Amount $ 50,265,902          
Investment Company, Portfolio Turnover 62.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks99.1%Software11%
Short-Term Investments0.9%Hotels, Restaurants and Leisure10%
Other Assets and Liabilities0.0%Aerospace and Defense7%
 Health Care Equipment and Supplies5%
 Biotechnology5%
          
C000017094 [Member]            
Shareholder Report [Line Items]            
Fund Name Large Cap Equity Fund          
Class Name Investor Class          
Trading Symbol AFDIX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Large Cap Equity Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Investor Class$850.79%
          
Expenses Paid, Amount $ 85          
Expense Ratio, Percent 0.79%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Large Cap Equity Fund Investor Class returned 14.53% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. Income is a secondary objective. The commentary below refers to the fund's performance compared to the S&P 500 Index.
•
Stock selection in the communication services sector contributed most to relative performance. It helped to avoid shares of poor-performing media companies. An overweight to internet search giant Alphabet, parent of Google and YouTube, was a leading contributor to relative results. The company's results benefited from artificial intelligence (AI)-enhanced advertising placement and content creation.
•
Among individual contributors, a notable source of strength was a stake in commercial building solutions company Johnson Controls International. The stock benefited from strong demand for its energy-efficiency and cooling solutions, particularly as they relate to the ongoing AI-related data center build-out.
•
In information technology, semiconductors and semiconductor equipment stocks hurt relative results. Several of the leading detractors are explained by their exposure to AI. A notable relative detractor was an underweight to AI chipmaker Advanced Micro Devices. It also hurt to have no expsoure to shares of AI software and consulting firm Palantir Technologies.
•
Positioning in the health care sector also detracted from performance. Health care provider and services giant UnitedHealth Group was the leading detractor in the sector. A stake in pharmaceuticals company Novo Nordisk, maker of popular weight-loss drug Ozempic, was another source of weakness.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
October 31, 2015 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 Year10 Year
Investor Class14.53%14.49%13.23%
S&P 50021.45%17.64%14.64%
          
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 3,404,760,198 $ 3,404,760,198 $ 3,404,760,198 $ 3,404,760,198 $ 3,404,760,198 $ 3,404,760,198
Holdings Count | holding 100 100 100 100 100 100
Advisory Fees Paid, Amount $ 11,078,510          
Investment Company, Portfolio Turnover 44.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks100.0%Semiconductors and Semiconductor Equipment15%
Short-Term Investments0.2%Software12%
Other Assets and Liabilities(0.2)%Interactive Media and Services8%
 Technology Hardware, Storage and Peripherals5%
 Capital Markets4%
          
C000017095 [Member]            
Shareholder Report [Line Items]            
Fund Name Large Cap Equity Fund          
Class Name I Class          
Trading Symbol AFEIX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Large Cap Equity Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
I Class$630.59%
          
Expenses Paid, Amount $ 63          
Expense Ratio, Percent 0.59%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Large Cap Equity Fund I Class returned 14.73% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. Income is a secondary objective. The commentary below refers to the fund's performance compared to the S&P 500 Index.
•
Stock selection in the communication services sector contributed most to relative performance. It helped to avoid shares of poor-performing media companies. An overweight to internet search giant Alphabet, parent of Google and YouTube, was a leading contributor to relative results. The company's results benefited from artificial intelligence (AI)-enhanced advertising placement and content creation.
•
Among individual contributors, a notable source of strength was a stake in commercial building solutions company Johnson Controls International. The stock benefited from strong demand for its energy-efficiency and cooling solutions, particularly as they relate to the ongoing AI-related data center build-out.
•
In information technology, semiconductors and semiconductor equipment stocks hurt relative results. Several of the leading detractors are explained by their exposure to AI. A notable relative detractor was an underweight to AI chipmaker Advanced Micro Devices. It also hurt to have no expsoure to shares of AI software and consulting firm Palantir Technologies.
•
Positioning in the health care sector also detracted from performance. Health care provider and services giant UnitedHealth Group was the leading detractor in the sector. A stake in pharmaceuticals company Novo Nordisk, maker of popular weight-loss drug Ozempic, was another source of weakness.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
October 31, 2015 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 Year10 Year
I Class14.73%14.72%13.46%
S&P 50021.45%17.64%14.64%
          
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 3,404,760,198 $ 3,404,760,198 $ 3,404,760,198 $ 3,404,760,198 $ 3,404,760,198 $ 3,404,760,198
Holdings Count | holding 100 100 100 100 100 100
Advisory Fees Paid, Amount $ 11,078,510          
Investment Company, Portfolio Turnover 44.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks100.0%Semiconductors and Semiconductor Equipment15%
Short-Term Investments0.2%Software12%
Other Assets and Liabilities(0.2)%Interactive Media and Services8%
 Technology Hardware, Storage and Peripherals5%
 Capital Markets4%
          
C000189742 [Member]            
Shareholder Report [Line Items]            
Fund Name Large Cap Equity Fund          
Class Name Y Class          
Trading Symbol AFYDX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Large Cap Equity Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Y Class$470.44%
          
Expenses Paid, Amount $ 47          
Expense Ratio, Percent 0.44%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Large Cap Equity Fund Y Class returned 14.92% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. Income is a secondary objective. The commentary below refers to the fund's performance compared to the S&P 500 Index.
•
Stock selection in the communication services sector contributed most to relative performance. It helped to avoid shares of poor-performing media companies. An overweight to internet search giant Alphabet, parent of Google and YouTube, was a leading contributor to relative results. The company's results benefited from artificial intelligence (AI)-enhanced advertising placement and content creation.
•
Among individual contributors, a notable source of strength was a stake in commercial building solutions company Johnson Controls International. The stock benefited from strong demand for its energy-efficiency and cooling solutions, particularly as they relate to the ongoing AI-related data center build-out.
•
In information technology, semiconductors and semiconductor equipment stocks hurt relative results. Several of the leading detractors are explained by their exposure to AI. A notable relative detractor was an underweight to AI chipmaker Advanced Micro Devices. It also hurt to have no expsoure to shares of AI software and consulting firm Palantir Technologies.
•
Positioning in the health care sector also detracted from performance. Health care provider and services giant UnitedHealth Group was the leading detractor in the sector. A stake in pharmaceuticals company Novo Nordisk, maker of popular weight-loss drug Ozempic, was another source of weakness.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
April 10, 2017 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 YearSince InceptionInception Date
Y Class14.92%14.89%14.50%4/10/17
S&P 50021.45%17.64%15.16%—
          
Performance Inception Date           Apr. 10, 2017
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 3,404,760,198 $ 3,404,760,198 $ 3,404,760,198 $ 3,404,760,198 $ 3,404,760,198 $ 3,404,760,198
Holdings Count | holding 100 100 100 100 100 100
Advisory Fees Paid, Amount $ 11,078,510          
Investment Company, Portfolio Turnover 44.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks100.0%Semiconductors and Semiconductor Equipment15%
Short-Term Investments0.2%Software12%
Other Assets and Liabilities(0.2)%Interactive Media and Services8%
 Technology Hardware, Storage and Peripherals5%
 Capital Markets4%
          
C000017096 [Member]            
Shareholder Report [Line Items]            
Fund Name Large Cap Equity Fund          
Class Name A Class          
Trading Symbol AFDAX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Large Cap Equity Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
A Class$1111.04%
          
Expenses Paid, Amount $ 111          
Expense Ratio, Percent 1.04%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Large Cap Equity Fund A Class returned 14.22% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. Income is a secondary objective. The commentary below refers to the fund's performance compared to the S&P 500 Index.
•
Stock selection in the communication services sector contributed most to relative performance. It helped to avoid shares of poor-performing media companies. An overweight to internet search giant Alphabet, parent of Google and YouTube, was a leading contributor to relative results. The company's results benefited from artificial intelligence (AI)-enhanced advertising placement and content creation.
•
Among individual contributors, a notable source of strength was a stake in commercial building solutions company Johnson Controls International. The stock benefited from strong demand for its energy-efficiency and cooling solutions, particularly as they relate to the ongoing AI-related data center build-out.
•
In information technology, semiconductors and semiconductor equipment stocks hurt relative results. Several of the leading detractors are explained by their exposure to AI. A notable relative detractor was an underweight to AI chipmaker Advanced Micro Devices. It also hurt to have no expsoure to shares of AI software and consulting firm Palantir Technologies.
•
Positioning in the health care sector also detracted from performance. Health care provider and services giant UnitedHealth Group was the leading detractor in the sector. A stake in pharmaceuticals company Novo Nordisk, maker of popular weight-loss drug Ozempic, was another source of weakness.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
October 31, 2015 through October 31, 2025
The initial investment is adjusted to reflect the maximum initial sales charge.
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 Year10 Year
A Class14.22%14.20%12.95%
A Class - with sales charge7.66%12.86%12.29%
S&P 50021.45%17.64%14.64%
          
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 3,404,760,198 $ 3,404,760,198 $ 3,404,760,198 $ 3,404,760,198 $ 3,404,760,198 $ 3,404,760,198
Holdings Count | holding 100 100 100 100 100 100
Advisory Fees Paid, Amount $ 11,078,510          
Investment Company, Portfolio Turnover 44.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks100.0%Semiconductors and Semiconductor Equipment15%
Short-Term Investments0.2%Software12%
Other Assets and Liabilities(0.2)%Interactive Media and Services8%
 Technology Hardware, Storage and Peripherals5%
 Capital Markets4%
          
C000017098 [Member]            
Shareholder Report [Line Items]            
Fund Name Large Cap Equity Fund          
Class Name C Class          
Trading Symbol AFDCX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Large Cap Equity Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
C Class$1911.79%
          
Expenses Paid, Amount $ 191          
Expense Ratio, Percent 1.79%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Large Cap Equity Fund C Class returned 13.37% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. Income is a secondary objective. The commentary below refers to the fund's performance compared to the S&P 500 Index.
•
Stock selection in the communication services sector contributed most to relative performance. It helped to avoid shares of poor-performing media companies. An overweight to internet search giant Alphabet, parent of Google and YouTube, was a leading contributor to relative results. The company's results benefited from artificial intelligence (AI)-enhanced advertising placement and content creation.
•
Among individual contributors, a notable source of strength was a stake in commercial building solutions company Johnson Controls International. The stock benefited from strong demand for its energy-efficiency and cooling solutions, particularly as they relate to the ongoing AI-related data center build-out.
•
In information technology, semiconductors and semiconductor equipment stocks hurt relative results. Several of the leading detractors are explained by their exposure to AI. A notable relative detractor was an underweight to AI chipmaker Advanced Micro Devices. It also hurt to have no expsoure to shares of AI software and consulting firm Palantir Technologies.
•
Positioning in the health care sector also detracted from performance. Health care provider and services giant UnitedHealth Group was the leading detractor in the sector. A stake in pharmaceuticals company Novo Nordisk, maker of popular weight-loss drug Ozempic, was another source of weakness.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
October 31, 2015 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 Year10 Year
C Class13.37%13.35%12.11%
S&P 50021.45%17.64%14.64%
          
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 3,404,760,198 $ 3,404,760,198 $ 3,404,760,198 $ 3,404,760,198 $ 3,404,760,198 $ 3,404,760,198
Holdings Count | holding 100 100 100 100 100 100
Advisory Fees Paid, Amount $ 11,078,510          
Investment Company, Portfolio Turnover 44.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks100.0%Semiconductors and Semiconductor Equipment15%
Short-Term Investments0.2%Software12%
Other Assets and Liabilities(0.2)%Interactive Media and Services8%
 Technology Hardware, Storage and Peripherals5%
 Capital Markets4%
          
C000017099 [Member]            
Shareholder Report [Line Items]            
Fund Name Large Cap Equity Fund          
Class Name R Class          
Trading Symbol AFDRX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Large Cap Equity Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
R Class$1381.29%
          
Expenses Paid, Amount $ 138          
Expense Ratio, Percent 1.29%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Large Cap Equity Fund R Class returned 13.96% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. Income is a secondary objective. The commentary below refers to the fund's performance compared to the S&P 500 Index.
•
Stock selection in the communication services sector contributed most to relative performance. It helped to avoid shares of poor-performing media companies. An overweight to internet search giant Alphabet, parent of Google and YouTube, was a leading contributor to relative results. The company's results benefited from artificial intelligence (AI)-enhanced advertising placement and content creation.
•
Among individual contributors, a notable source of strength was a stake in commercial building solutions company Johnson Controls International. The stock benefited from strong demand for its energy-efficiency and cooling solutions, particularly as they relate to the ongoing AI-related data center build-out.
•
In information technology, semiconductors and semiconductor equipment stocks hurt relative results. Several of the leading detractors are explained by their exposure to AI. A notable relative detractor was an underweight to AI chipmaker Advanced Micro Devices. It also hurt to have no expsoure to shares of AI software and consulting firm Palantir Technologies.
•
Positioning in the health care sector also detracted from performance. Health care provider and services giant UnitedHealth Group was the leading detractor in the sector. A stake in pharmaceuticals company Novo Nordisk, maker of popular weight-loss drug Ozempic, was another source of weakness.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
October 31, 2015 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 Year10 Year
R Class13.96%13.92%12.67%
S&P 50021.45%17.64%14.64%
          
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 3,404,760,198 $ 3,404,760,198 $ 3,404,760,198 $ 3,404,760,198 $ 3,404,760,198 $ 3,404,760,198
Holdings Count | holding 100 100 100 100 100 100
Advisory Fees Paid, Amount $ 11,078,510          
Investment Company, Portfolio Turnover 44.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks100.0%Semiconductors and Semiconductor Equipment15%
Short-Term Investments0.2%Software12%
Other Assets and Liabilities(0.2)%Interactive Media and Services8%
 Technology Hardware, Storage and Peripherals5%
 Capital Markets4%
          
C000189741 [Member]            
Shareholder Report [Line Items]            
Fund Name Large Cap Equity Fund          
Class Name R5 Class          
Trading Symbol AFDGX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Large Cap Equity Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
R5 Class$630.59%
          
Expenses Paid, Amount $ 63          
Expense Ratio, Percent 0.59%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Large Cap Equity Fund R5 Class returned 14.74% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. Income is a secondary objective. The commentary below refers to the fund's performance compared to the S&P 500 Index.
•
Stock selection in the communication services sector contributed most to relative performance. It helped to avoid shares of poor-performing media companies. An overweight to internet search giant Alphabet, parent of Google and YouTube, was a leading contributor to relative results. The company's results benefited from artificial intelligence (AI)-enhanced advertising placement and content creation.
•
Among individual contributors, a notable source of strength was a stake in commercial building solutions company Johnson Controls International. The stock benefited from strong demand for its energy-efficiency and cooling solutions, particularly as they relate to the ongoing AI-related data center build-out.
•
In information technology, semiconductors and semiconductor equipment stocks hurt relative results. Several of the leading detractors are explained by their exposure to AI. A notable relative detractor was an underweight to AI chipmaker Advanced Micro Devices. It also hurt to have no expsoure to shares of AI software and consulting firm Palantir Technologies.
•
Positioning in the health care sector also detracted from performance. Health care provider and services giant UnitedHealth Group was the leading detractor in the sector. A stake in pharmaceuticals company Novo Nordisk, maker of popular weight-loss drug Ozempic, was another source of weakness.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
April 10, 2017 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 YearSince InceptionInception Date
R5 Class14.74%14.72%14.33%4/10/17
S&P 50021.45%17.64%15.16%—
          
Performance Inception Date           Apr. 10, 2017
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 3,404,760,198 $ 3,404,760,198 $ 3,404,760,198 $ 3,404,760,198 $ 3,404,760,198 $ 3,404,760,198
Holdings Count | holding 100 100 100 100 100 100
Advisory Fees Paid, Amount $ 11,078,510          
Investment Company, Portfolio Turnover 44.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks100.0%Semiconductors and Semiconductor Equipment15%
Short-Term Investments0.2%Software12%
Other Assets and Liabilities(0.2)%Interactive Media and Services8%
 Technology Hardware, Storage and Peripherals5%
 Capital Markets4%
          
C000212514 [Member]            
Shareholder Report [Line Items]            
Fund Name Large Cap Equity Fund          
Class Name R6 Class          
Trading Symbol AFEDX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Large Cap Equity Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
R6 Class$470.44%
          
Expenses Paid, Amount $ 47          
Expense Ratio, Percent 0.44%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Large Cap Equity Fund R6 Class returned 14.93% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. Income is a secondary objective. The commentary below refers to the fund's performance compared to the S&P 500 Index.
•
Stock selection in the communication services sector contributed most to relative performance. It helped to avoid shares of poor-performing media companies. An overweight to internet search giant Alphabet, parent of Google and YouTube, was a leading contributor to relative results. The company's results benefited from artificial intelligence (AI)-enhanced advertising placement and content creation.
•
Among individual contributors, a notable source of strength was a stake in commercial building solutions company Johnson Controls International. The stock benefited from strong demand for its energy-efficiency and cooling solutions, particularly as they relate to the ongoing AI-related data center build-out.
•
In information technology, semiconductors and semiconductor equipment stocks hurt relative results. Several of the leading detractors are explained by their exposure to AI. A notable relative detractor was an underweight to AI chipmaker Advanced Micro Devices. It also hurt to have no expsoure to shares of AI software and consulting firm Palantir Technologies.
•
Positioning in the health care sector also detracted from performance. Health care provider and services giant UnitedHealth Group was the leading detractor in the sector. A stake in pharmaceuticals company Novo Nordisk, maker of popular weight-loss drug Ozempic, was another source of weakness.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
April 1, 2019 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 YearSince InceptionInception Date
R6 Class14.93%14.89%14.47%4/1/19
S&P 50021.45%17.64%15.93%—
          
Performance Inception Date         Apr. 01, 2019  
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 3,404,760,198 $ 3,404,760,198 $ 3,404,760,198 $ 3,404,760,198 $ 3,404,760,198 $ 3,404,760,198
Holdings Count | holding 100 100 100 100 100 100
Advisory Fees Paid, Amount $ 11,078,510          
Investment Company, Portfolio Turnover 44.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks100.0%Semiconductors and Semiconductor Equipment15%
Short-Term Investments0.2%Software12%
Other Assets and Liabilities(0.2)%Interactive Media and Services8%
 Technology Hardware, Storage and Peripherals5%
 Capital Markets4%
          
C000212513 [Member]            
Shareholder Report [Line Items]            
Fund Name Large Cap Equity Fund          
Class Name G Class          
Trading Symbol AFEGX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Large Cap Equity Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
G Class$00.00%
          
Expenses Paid, Amount $ 0          
Expense Ratio, Percent 0.00%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Large Cap Equity Fund G Class returned 15.42% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. Income is a secondary objective. The commentary below refers to the fund's performance compared to the S&P 500 Index.
•
Stock selection in the communication services sector contributed most to relative performance. It helped to avoid shares of poor-performing media companies. An overweight to internet search giant Alphabet, parent of Google and YouTube, was a leading contributor to relative results. The company's results benefited from artificial intelligence (AI)-enhanced advertising placement and content creation.
•
Among individual contributors, a notable source of strength was a stake in commercial building solutions company Johnson Controls International. The stock benefited from strong demand for its energy-efficiency and cooling solutions, particularly as they relate to the ongoing AI-related data center build-out.
•
In information technology, semiconductors and semiconductor equipment stocks hurt relative results. Several of the leading detractors are explained by their exposure to AI. A notable relative detractor was an underweight to AI chipmaker Advanced Micro Devices. It also hurt to have no expsoure to shares of AI software and consulting firm Palantir Technologies.
•
Positioning in the health care sector also detracted from performance. Health care provider and services giant UnitedHealth Group was the leading detractor in the sector. A stake in pharmaceuticals company Novo Nordisk, maker of popular weight-loss drug Ozempic, was another source of weakness.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
April 1, 2019 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 YearSince InceptionInception Date
G Class15.42%15.39%14.97%4/1/19
S&P 50021.45%17.64%15.93%—
          
Performance Inception Date         Apr. 01, 2019  
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 3,404,760,198 $ 3,404,760,198 $ 3,404,760,198 $ 3,404,760,198 $ 3,404,760,198 $ 3,404,760,198
Holdings Count | holding 100 100 100 100 100 100
Advisory Fees Paid, Amount $ 11,078,510          
Investment Company, Portfolio Turnover 44.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks100.0%Semiconductors and Semiconductor Equipment15%
Short-Term Investments0.2%Software12%
Other Assets and Liabilities(0.2)%Interactive Media and Services8%
 Technology Hardware, Storage and Peripherals5%
 Capital Markets4%
          
C000017053 [Member]            
Shareholder Report [Line Items]            
Fund Name Select Fund          
Class Name Investor Class          
Trading Symbol TWCIX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Select Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Investor Class$1010.90%
          
Expenses Paid, Amount $ 101          
Expense Ratio, Percent 0.90%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Select Fund Investor Class returned 24.98% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund’s performance compared to the Russell 1000 Growth Index.
•
Stock selection in the consumer discretionary sector contributed most to relative performance. It helped to underweight the shares of hotels, restaurants and leisure companies, as well as those of textiles, apparel and luxury goods makers. In general, these stocks suffered from weaker spending by lower-income and price-sensitive consumers.
•
An underweight allocation to the communication services sector benefited relative performance. In addition, a position in internet search giant Alphabet, parent of Google and YouTube, was a leading contributor to relative results. The company’s results benefited from artificial intelligence (AI)-enhanced advertising placement and content creation.
•
In information technology, software and semiconductors and semiconductor equipment companies hurt relative results. Several othe leading detractors are explained by their exposure to AI. The top relative detractor was AI chipmaker Broadcom, to which we had limited exposure. It also hurt to be underrepresented in shares of AI software and consulting firm Palantir Technologies.
•
Holdings in the health care sector also detracted from performance. Biotechnology company Regeneron Pharmaceuticals and health care provider and services giant UnitedHealth Group were the top detractors in health care.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
October 31, 2015 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 Year10 Year
Investor Class24.98%16.28%15.91%
Regulatory Index
Russell 100021.14%17.05%14.39%
Performance Index
Russell 1000 Growth30.52%19.24%18.28%
          
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 6,666,417,651 $ 6,666,417,651 $ 6,666,417,651 $ 6,666,417,651 $ 6,666,417,651 $ 6,666,417,651
Holdings Count | holding 57 57 57 57 57 57
Advisory Fees Paid, Amount $ 48,840,357          
Investment Company, Portfolio Turnover 22.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks99.8%Semiconductors and Semiconductor Equipment24%
Short-Term Investments0.4%Software17%
Other Assets and Liabilities(0.2)%Interactive Media and Services15%
 Technology Hardware, Storage and Peripherals9%
 Broadline Retail8%
          
C000017055 [Member]            
Shareholder Report [Line Items]            
Fund Name Select Fund          
Class Name I Class          
Trading Symbol TWSIX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Select Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
I Class$790.70%
          
Expenses Paid, Amount $ 79          
Expense Ratio, Percent 0.70%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Select Fund I Class returned 25.23% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund’s performance compared to the Russell 1000 Growth Index.
•
Stock selection in the consumer discretionary sector contributed most to relative performance. It helped to underweight the shares of hotels, restaurants and leisure companies, as well as those of textiles, apparel and luxury goods makers. In general, these stocks suffered from weaker spending by lower-income and price-sensitive consumers.
•
An underweight allocation to the communication services sector benefited relative performance. In addition, a position in internet search giant Alphabet, parent of Google and YouTube, was a leading contributor to relative results. The company’s results benefited from artificial intelligence (AI)-enhanced advertising placement and content creation.
•
In information technology, software and semiconductors and semiconductor equipment companies hurt relative results. Several othe leading detractors are explained by their exposure to AI. The top relative detractor was AI chipmaker Broadcom, to which we had limited exposure. It also hurt to be underrepresented in shares of AI software and consulting firm Palantir Technologies.
•
Holdings in the health care sector also detracted from performance. Biotechnology company Regeneron Pharmaceuticals and health care provider and services giant UnitedHealth Group were the top detractors in health care.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
October 31, 2015 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 Year10 Year
I Class25.23%16.51%16.14%
Regulatory Index
Russell 100021.14%17.05%14.39%
Performance Index
Russell 1000 Growth30.52%19.24%18.28%
          
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 6,666,417,651 $ 6,666,417,651 $ 6,666,417,651 $ 6,666,417,651 $ 6,666,417,651 $ 6,666,417,651
Holdings Count | holding 57 57 57 57 57 57
Advisory Fees Paid, Amount $ 48,840,357          
Investment Company, Portfolio Turnover 22.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks99.8%Semiconductors and Semiconductor Equipment24%
Short-Term Investments0.4%Software17%
Other Assets and Liabilities(0.2)%Interactive Media and Services15%
 Technology Hardware, Storage and Peripherals9%
 Broadline Retail8%
          
C000189738 [Member]            
Shareholder Report [Line Items]            
Fund Name Select Fund          
Class Name Y Class          
Trading Symbol ASLWX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Select Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Y Class$620.55%
          
Expenses Paid, Amount $ 62          
Expense Ratio, Percent 0.55%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Select Fund Y Class returned 25.42% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund’s performance compared to the Russell 1000 Growth Index.
•
Stock selection in the consumer discretionary sector contributed most to relative performance. It helped to underweight the shares of hotels, restaurants and leisure companies, as well as those of textiles, apparel and luxury goods makers. In general, these stocks suffered from weaker spending by lower-income and price-sensitive consumers.
•
An underweight allocation to the communication services sector benefited relative performance. In addition, a position in internet search giant Alphabet, parent of Google and YouTube, was a leading contributor to relative results. The company’s results benefited from artificial intelligence (AI)-enhanced advertising placement and content creation.
•
In information technology, software and semiconductors and semiconductor equipment companies hurt relative results. Several othe leading detractors are explained by their exposure to AI. The top relative detractor was AI chipmaker Broadcom, to which we had limited exposure. It also hurt to be underrepresented in shares of AI software and consulting firm Palantir Technologies.
•
Holdings in the health care sector also detracted from performance. Biotechnology company Regeneron Pharmaceuticals and health care provider and services giant UnitedHealth Group were the top detractors in health care.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
April 10, 2017 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 YearSince InceptionInception Date
Y Class25.42%16.68%17.54%4/10/17
Regulatory Index
Russell 100021.14%17.05%14.89%—
Performance Index
Russell 1000 Growth30.52%19.24%19.68%—
          
Performance Inception Date           Apr. 10, 2017
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 6,666,417,651 $ 6,666,417,651 $ 6,666,417,651 $ 6,666,417,651 $ 6,666,417,651 $ 6,666,417,651
Holdings Count | holding 57 57 57 57 57 57
Advisory Fees Paid, Amount $ 48,840,357          
Investment Company, Portfolio Turnover 22.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks99.8%Semiconductors and Semiconductor Equipment24%
Short-Term Investments0.4%Software17%
Other Assets and Liabilities(0.2)%Interactive Media and Services15%
 Technology Hardware, Storage and Peripherals9%
 Broadline Retail8%
          
C000017054 [Member]            
Shareholder Report [Line Items]            
Fund Name Select Fund          
Class Name A Class          
Trading Symbol TWCAX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Select Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
A Class$1291.15%
          
Expenses Paid, Amount $ 129          
Expense Ratio, Percent 1.15%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Select Fund A Class returned 24.67% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund’s performance compared to the Russell 1000 Growth Index.
•
Stock selection in the consumer discretionary sector contributed most to relative performance. It helped to underweight the shares of hotels, restaurants and leisure companies, as well as those of textiles, apparel and luxury goods makers. In general, these stocks suffered from weaker spending by lower-income and price-sensitive consumers.
•
An underweight allocation to the communication services sector benefited relative performance. In addition, a position in internet search giant Alphabet, parent of Google and YouTube, was a leading contributor to relative results. The company’s results benefited from artificial intelligence (AI)-enhanced advertising placement and content creation.
•
In information technology, software and semiconductors and semiconductor equipment companies hurt relative results. Several othe leading detractors are explained by their exposure to AI. The top relative detractor was AI chipmaker Broadcom, to which we had limited exposure. It also hurt to be underrepresented in shares of AI software and consulting firm Palantir Technologies.
•
Holdings in the health care sector also detracted from performance. Biotechnology company Regeneron Pharmaceuticals and health care provider and services giant UnitedHealth Group were the top detractors in health care.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
October 31, 2015 through October 31, 2025
The initial investment is adjusted to reflect the maximum initial sales charge.
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 Year10 Year
A Class24.67%15.98%15.61%
A Class - with sales charge17.50%14.62%14.93%
Regulatory Index
Russell 100021.14%17.05%14.39%
Performance Index
Russell 1000 Growth30.52%19.24%18.28%
          
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 6,666,417,651 $ 6,666,417,651 $ 6,666,417,651 $ 6,666,417,651 $ 6,666,417,651 $ 6,666,417,651
Holdings Count | holding 57 57 57 57 57 57
Advisory Fees Paid, Amount $ 48,840,357          
Investment Company, Portfolio Turnover 22.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks99.8%Semiconductors and Semiconductor Equipment24%
Short-Term Investments0.4%Software17%
Other Assets and Liabilities(0.2)%Interactive Media and Services15%
 Technology Hardware, Storage and Peripherals9%
 Broadline Retail8%
          
C000017058 [Member]            
Shareholder Report [Line Items]            
Fund Name Select Fund          
Class Name C Class          
Trading Symbol ACSLX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Select Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
C Class$2131.90%
          
Expenses Paid, Amount $ 213          
Expense Ratio, Percent 1.90%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Select Fund C Class returned 23.73% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund’s performance compared to the Russell 1000 Growth Index.
•
Stock selection in the consumer discretionary sector contributed most to relative performance. It helped to underweight the shares of hotels, restaurants and leisure companies, as well as those of textiles, apparel and luxury goods makers. In general, these stocks suffered from weaker spending by lower-income and price-sensitive consumers.
•
An underweight allocation to the communication services sector benefited relative performance. In addition, a position in internet search giant Alphabet, parent of Google and YouTube, was a leading contributor to relative results. The company’s results benefited from artificial intelligence (AI)-enhanced advertising placement and content creation.
•
In information technology, software and semiconductors and semiconductor equipment companies hurt relative results. Several othe leading detractors are explained by their exposure to AI. The top relative detractor was AI chipmaker Broadcom, to which we had limited exposure. It also hurt to be underrepresented in shares of AI software and consulting firm Palantir Technologies.
•
Holdings in the health care sector also detracted from performance. Biotechnology company Regeneron Pharmaceuticals and health care provider and services giant UnitedHealth Group were the top detractors in health care.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
October 31, 2015 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 Year10 Year
C Class23.73%15.12%14.75%
Regulatory Index
Russell 100021.14%17.05%14.39%
Performance Index
Russell 1000 Growth30.52%19.24%18.28%
          
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 6,666,417,651 $ 6,666,417,651 $ 6,666,417,651 $ 6,666,417,651 $ 6,666,417,651 $ 6,666,417,651
Holdings Count | holding 57 57 57 57 57 57
Advisory Fees Paid, Amount $ 48,840,357          
Investment Company, Portfolio Turnover 22.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks99.8%Semiconductors and Semiconductor Equipment24%
Short-Term Investments0.4%Software17%
Other Assets and Liabilities(0.2)%Interactive Media and Services15%
 Technology Hardware, Storage and Peripherals9%
 Broadline Retail8%
          
C000017059 [Member]            
Shareholder Report [Line Items]            
Fund Name Select Fund          
Class Name R Class          
Trading Symbol ASERX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Select Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
R Class$1571.40%
          
Expenses Paid, Amount $ 157          
Expense Ratio, Percent 1.40%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Select Fund R Class returned 24.36% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund’s performance compared to the Russell 1000 Growth Index.
•
Stock selection in the consumer discretionary sector contributed most to relative performance. It helped to underweight the shares of hotels, restaurants and leisure companies, as well as those of textiles, apparel and luxury goods makers. In general, these stocks suffered from weaker spending by lower-income and price-sensitive consumers.
•
An underweight allocation to the communication services sector benefited relative performance. In addition, a position in internet search giant Alphabet, parent of Google and YouTube, was a leading contributor to relative results. The company’s results benefited from artificial intelligence (AI)-enhanced advertising placement and content creation.
•
In information technology, software and semiconductors and semiconductor equipment companies hurt relative results. Several othe leading detractors are explained by their exposure to AI. The top relative detractor was AI chipmaker Broadcom, to which we had limited exposure. It also hurt to be underrepresented in shares of AI software and consulting firm Palantir Technologies.
•
Holdings in the health care sector also detracted from performance. Biotechnology company Regeneron Pharmaceuticals and health care provider and services giant UnitedHealth Group were the top detractors in health care.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
October 31, 2015 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 Year10 Year
R Class24.36%15.70%15.33%
Regulatory Index
Russell 100021.14%17.05%14.39%
Performance Index
Russell 1000 Growth30.52%19.24%18.28%
          
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 6,666,417,651 $ 6,666,417,651 $ 6,666,417,651 $ 6,666,417,651 $ 6,666,417,651 $ 6,666,417,651
Holdings Count | holding 57 57 57 57 57 57
Advisory Fees Paid, Amount $ 48,840,357          
Investment Company, Portfolio Turnover 22.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks99.8%Semiconductors and Semiconductor Equipment24%
Short-Term Investments0.4%Software17%
Other Assets and Liabilities(0.2)%Interactive Media and Services15%
 Technology Hardware, Storage and Peripherals9%
 Broadline Retail8%
          
C000189737 [Member]            
Shareholder Report [Line Items]            
Fund Name Select Fund          
Class Name R5 Class          
Trading Symbol ASLGX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Select Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
R5 Class$790.70%
          
Expenses Paid, Amount $ 79          
Expense Ratio, Percent 0.70%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Select Fund R5 Class returned 25.24% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund’s performance compared to the Russell 1000 Growth Index.
•
Stock selection in the consumer discretionary sector contributed most to relative performance. It helped to underweight the shares of hotels, restaurants and leisure companies, as well as those of textiles, apparel and luxury goods makers. In general, these stocks suffered from weaker spending by lower-income and price-sensitive consumers.
•
An underweight allocation to the communication services sector benefited relative performance. In addition, a position in internet search giant Alphabet, parent of Google and YouTube, was a leading contributor to relative results. The company’s results benefited from artificial intelligence (AI)-enhanced advertising placement and content creation.
•
In information technology, software and semiconductors and semiconductor equipment companies hurt relative results. Several othe leading detractors are explained by their exposure to AI. The top relative detractor was AI chipmaker Broadcom, to which we had limited exposure. It also hurt to be underrepresented in shares of AI software and consulting firm Palantir Technologies.
•
Holdings in the health care sector also detracted from performance. Biotechnology company Regeneron Pharmaceuticals and health care provider and services giant UnitedHealth Group were the top detractors in health care.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
April 10, 2017 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 YearSince InceptionInception Date
R5 Class25.24%16.51%17.36%4/10/17
Regulatory Index
Russell 100021.14%17.05%14.89%—
Performance Index
Russell 1000 Growth30.52%19.24%19.68%—
          
Performance Inception Date           Apr. 10, 2017
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 6,666,417,651 $ 6,666,417,651 $ 6,666,417,651 $ 6,666,417,651 $ 6,666,417,651 $ 6,666,417,651
Holdings Count | holding 57 57 57 57 57 57
Advisory Fees Paid, Amount $ 48,840,357          
Investment Company, Portfolio Turnover 22.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks99.8%Semiconductors and Semiconductor Equipment24%
Short-Term Investments0.4%Software17%
Other Assets and Liabilities(0.2)%Interactive Media and Services15%
 Technology Hardware, Storage and Peripherals9%
 Broadline Retail8%
          
C000131597 [Member]            
Shareholder Report [Line Items]            
Fund Name Select Fund          
Class Name R6 Class          
Trading Symbol ASDEX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Select Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
R6 Class$620.55%
          
Expenses Paid, Amount $ 62          
Expense Ratio, Percent 0.55%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Select Fund R6 Class returned 25.42% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund’s performance compared to the Russell 1000 Growth Index.
•
Stock selection in the consumer discretionary sector contributed most to relative performance. It helped to underweight the shares of hotels, restaurants and leisure companies, as well as those of textiles, apparel and luxury goods makers. In general, these stocks suffered from weaker spending by lower-income and price-sensitive consumers.
•
An underweight allocation to the communication services sector benefited relative performance. In addition, a position in internet search giant Alphabet, parent of Google and YouTube, was a leading contributor to relative results. The company’s results benefited from artificial intelligence (AI)-enhanced advertising placement and content creation.
•
In information technology, software and semiconductors and semiconductor equipment companies hurt relative results. Several othe leading detractors are explained by their exposure to AI. The top relative detractor was AI chipmaker Broadcom, to which we had limited exposure. It also hurt to be underrepresented in shares of AI software and consulting firm Palantir Technologies.
•
Holdings in the health care sector also detracted from performance. Biotechnology company Regeneron Pharmaceuticals and health care provider and services giant UnitedHealth Group were the top detractors in health care.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
October 31, 2015 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 Year10 Year
R6 Class25.42%16.69%16.31%
Regulatory Index
Russell 100021.14%17.05%14.39%
Performance Index
Russell 1000 Growth30.52%19.24%18.28%
          
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 6,666,417,651 $ 6,666,417,651 $ 6,666,417,651 $ 6,666,417,651 $ 6,666,417,651 $ 6,666,417,651
Holdings Count | holding 57 57 57 57 57 57
Advisory Fees Paid, Amount $ 48,840,357          
Investment Company, Portfolio Turnover 22.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks99.8%Semiconductors and Semiconductor Equipment24%
Short-Term Investments0.4%Software17%
Other Assets and Liabilities(0.2)%Interactive Media and Services15%
 Technology Hardware, Storage and Peripherals9%
 Broadline Retail8%
          
C000247666 [Member]            
Shareholder Report [Line Items]            
Fund Name Select Fund          
Class Name G Class          
Trading Symbol ASLDX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Select Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
G Class$00.00%
          
Expenses Paid, Amount $ 0          
Expense Ratio, Percent 0.00%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Select Fund G Class returned 26.12% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund’s performance compared to the Russell 1000 Growth Index.
•
Stock selection in the consumer discretionary sector contributed most to relative performance. It helped to underweight the shares of hotels, restaurants and leisure companies, as well as those of textiles, apparel and luxury goods makers. In general, these stocks suffered from weaker spending by lower-income and price-sensitive consumers.
•
An underweight allocation to the communication services sector benefited relative performance. In addition, a position in internet search giant Alphabet, parent of Google and YouTube, was a leading contributor to relative results. The company’s results benefited from artificial intelligence (AI)-enhanced advertising placement and content creation.
•
In information technology, software and semiconductors and semiconductor equipment companies hurt relative results. Several othe leading detractors are explained by their exposure to AI. The top relative detractor was AI chipmaker Broadcom, to which we had limited exposure. It also hurt to be underrepresented in shares of AI software and consulting firm Palantir Technologies.
•
Holdings in the health care sector also detracted from performance. Biotechnology company Regeneron Pharmaceuticals and health care provider and services giant UnitedHealth Group were the top detractors in health care.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
November 2, 2023 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 YearSince InceptionInception Date
G Class26.12%29.95%11/2/23
Regulatory Index
Russell 100021.14%27.50%—
Performance Index
Russell 1000 Growth30.52%34.80%—
          
Performance Inception Date   Nov. 02, 2023        
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 6,666,417,651 $ 6,666,417,651 $ 6,666,417,651 $ 6,666,417,651 $ 6,666,417,651 $ 6,666,417,651
Holdings Count | holding 57 57 57 57 57 57
Advisory Fees Paid, Amount $ 48,840,357          
Investment Company, Portfolio Turnover 22.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks99.8%Semiconductors and Semiconductor Equipment24%
Short-Term Investments0.4%Software17%
Other Assets and Liabilities(0.2)%Interactive Media and Services15%
 Technology Hardware, Storage and Peripherals9%
 Broadline Retail8%
          
C000017049 [Member]            
Shareholder Report [Line Items]            
Fund Name Small Cap Growth Fund          
Class Name Investor Class          
Trading Symbol ANOIX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Small Cap Growth Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Investor Class$1201.13%
          
Expenses Paid, Amount $ 120          
Expense Ratio, Percent 1.13%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Small Cap Growth Fund Investor Class returned 11.97% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund’s performance compared to the Russell 2000 Growth Index.
•
Stock selection in the health care sector contributed the most to the portfolio’s relative performance. While the portfolio took an underweight position in biotechnology, it had key holdings in companies like Natera, a genetic testing firm that was a portfolio-only stock. After a strong third quarter, the company significantly increased its guidance for the year.
•
Consumer discretionary was another important contributor due to stock selection. Owning Duolingo was key as the learning application company converted more freemium users to paid subscriptions and increased sales of its higher-priced family plans. In the hotels, restaurants and leisure industry, not owning companies like Sweetgreen, Shake Shack and Six Flags Entertainment helped.
•
The industrials sector acted as the leading detractor, largely due to stock selection. The portfolio did not own several key stocks in the electrical equipment industry, including Bloom Energy and Nextracker, which were part of the Russell 2000 Growth Index. Bloom has benefited from the artificial intelligence trend, which has fueled demand for its onsite power generation solutions.
•
Information technology was another notable detractor from the portfolio’s relative performance. In particular, our position in the semiconductors and semiconductor equipment industry was hurt by stock selection. We didn’t own Rigetti Computing, which was up on the potential for quantum computing solutions.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
October 31, 2015 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 Year10 Year
Investor Class11.97%7.61%12.02%
Regulatory Index
Russell 300020.81%16.74%14.08%
Performance Index
Russell 2000 Growth18.81%8.94%9.65%
          
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 4,937,399,531 $ 4,937,399,531 $ 4,937,399,531 $ 4,937,399,531 $ 4,937,399,531 $ 4,937,399,531
Holdings Count | holding 143 143 143 143 143 143
Advisory Fees Paid, Amount $ 37,731,195          
Investment Company, Portfolio Turnover 90.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks98.9%Biotechnology12%
Short-Term Investments4.1%Semiconductors and Semiconductor Equipment8%
Other Assets and Liabilities(3.0)%Software8%
 Electronic Equipment, Instruments and Components6%
 Aerospace and Defense6%
          
C000017048 [Member]            
Shareholder Report [Line Items]            
Fund Name Small Cap Growth Fund          
Class Name I Class          
Trading Symbol ANONX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Small Cap Growth Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
I Class$990.93%
          
Expenses Paid, Amount $ 99          
Expense Ratio, Percent 0.93%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Small Cap Growth Fund I Class returned 12.17% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund’s performance compared to the Russell 2000 Growth Index.
•
Stock selection in the health care sector contributed the most to the portfolio’s relative performance. While the portfolio took an underweight position in biotechnology, it had key holdings in companies like Natera, a genetic testing firm that was a portfolio-only stock. After a strong third quarter, the company significantly increased its guidance for the year.
•
Consumer discretionary was another important contributor due to stock selection. Owning Duolingo was key as the learning application company converted more freemium users to paid subscriptions and increased sales of its higher-priced family plans. In the hotels, restaurants and leisure industry, not owning companies like Sweetgreen, Shake Shack and Six Flags Entertainment helped.
•
The industrials sector acted as the leading detractor, largely due to stock selection. The portfolio did not own several key stocks in the electrical equipment industry, including Bloom Energy and Nextracker, which were part of the Russell 2000 Growth Index. Bloom has benefited from the artificial intelligence trend, which has fueled demand for its onsite power generation solutions.
•
Information technology was another notable detractor from the portfolio’s relative performance. In particular, our position in the semiconductors and semiconductor equipment industry was hurt by stock selection. We didn’t own Rigetti Computing, which was up on the potential for quantum computing solutions.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
October 31, 2015 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 Year10 Year
I Class12.17%7.82%12.25%
Regulatory Index
Russell 300020.81%16.74%14.08%
Performance Index
Russell 2000 Growth18.81%8.94%9.65%
          
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 4,937,399,531 $ 4,937,399,531 $ 4,937,399,531 $ 4,937,399,531 $ 4,937,399,531 $ 4,937,399,531
Holdings Count | holding 143 143 143 143 143 143
Advisory Fees Paid, Amount $ 37,731,195          
Investment Company, Portfolio Turnover 90.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks98.9%Biotechnology12%
Short-Term Investments4.1%Semiconductors and Semiconductor Equipment8%
Other Assets and Liabilities(3.0)%Software8%
 Electronic Equipment, Instruments and Components6%
 Aerospace and Defense6%
          
C000189736 [Member]            
Shareholder Report [Line Items]            
Fund Name Small Cap Growth Fund          
Class Name Y Class          
Trading Symbol ANOYX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Small Cap Growth Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Y Class$830.78%
          
Expenses Paid, Amount $ 83          
Expense Ratio, Percent 0.78%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Small Cap Growth Fund Y Class returned 12.31% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund’s performance compared to the Russell 2000 Growth Index.
•
Stock selection in the health care sector contributed the most to the portfolio’s relative performance. While the portfolio took an underweight position in biotechnology, it had key holdings in companies like Natera, a genetic testing firm that was a portfolio-only stock. After a strong third quarter, the company significantly increased its guidance for the year.
•
Consumer discretionary was another important contributor due to stock selection. Owning Duolingo was key as the learning application company converted more freemium users to paid subscriptions and increased sales of its higher-priced family plans. In the hotels, restaurants and leisure industry, not owning companies like Sweetgreen, Shake Shack and Six Flags Entertainment helped.
•
The industrials sector acted as the leading detractor, largely due to stock selection. The portfolio did not own several key stocks in the electrical equipment industry, including Bloom Energy and Nextracker, which were part of the Russell 2000 Growth Index. Bloom has benefited from the artificial intelligence trend, which has fueled demand for its onsite power generation solutions.
•
Information technology was another notable detractor from the portfolio’s relative performance. In particular, our position in the semiconductors and semiconductor equipment industry was hurt by stock selection. We didn’t own Rigetti Computing, which was up on the potential for quantum computing solutions.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
April 10, 2017 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 YearSince InceptionInception Date
Y Class12.31%7.98%12.76%4/10/17
Regulatory Index
Russell 300020.81%16.74%14.50%—
Performance Index
Russell 2000 Growth18.81%8.94%9.65%—
          
Performance Inception Date           Apr. 10, 2017
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 4,937,399,531 $ 4,937,399,531 $ 4,937,399,531 $ 4,937,399,531 $ 4,937,399,531 $ 4,937,399,531
Holdings Count | holding 143 143 143 143 143 143
Advisory Fees Paid, Amount $ 37,731,195          
Investment Company, Portfolio Turnover 90.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks98.9%Biotechnology12%
Short-Term Investments4.1%Semiconductors and Semiconductor Equipment8%
Other Assets and Liabilities(3.0)%Software8%
 Electronic Equipment, Instruments and Components6%
 Aerospace and Defense6%
          
C000017050 [Member]            
Shareholder Report [Line Items]            
Fund Name Small Cap Growth Fund          
Class Name A Class          
Trading Symbol ANOAX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Small Cap Growth Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
A Class$1461.38%
          
Expenses Paid, Amount $ 146          
Expense Ratio, Percent 1.38%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Small Cap Growth Fund A Class returned 11.63% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund’s performance compared to the Russell 2000 Growth Index.
•
Stock selection in the health care sector contributed the most to the portfolio’s relative performance. While the portfolio took an underweight position in biotechnology, it had key holdings in companies like Natera, a genetic testing firm that was a portfolio-only stock. After a strong third quarter, the company significantly increased its guidance for the year.
•
Consumer discretionary was another important contributor due to stock selection. Owning Duolingo was key as the learning application company converted more freemium users to paid subscriptions and increased sales of its higher-priced family plans. In the hotels, restaurants and leisure industry, not owning companies like Sweetgreen, Shake Shack and Six Flags Entertainment helped.
•
The industrials sector acted as the leading detractor, largely due to stock selection. The portfolio did not own several key stocks in the electrical equipment industry, including Bloom Energy and Nextracker, which were part of the Russell 2000 Growth Index. Bloom has benefited from the artificial intelligence trend, which has fueled demand for its onsite power generation solutions.
•
Information technology was another notable detractor from the portfolio’s relative performance. In particular, our position in the semiconductors and semiconductor equipment industry was hurt by stock selection. We didn’t own Rigetti Computing, which was up on the potential for quantum computing solutions.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
October 31, 2015 through October 31, 2025
The initial investment is adjusted to reflect the maximum initial sales charge.
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 Year10 Year
A Class11.63%7.34%11.74%
A Class - with sales charge5.21%6.08%11.08%
Regulatory Index
Russell 300020.81%16.74%14.08%
Performance Index
Russell 2000 Growth18.81%8.94%9.65%
          
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 4,937,399,531 $ 4,937,399,531 $ 4,937,399,531 $ 4,937,399,531 $ 4,937,399,531 $ 4,937,399,531
Holdings Count | holding 143 143 143 143 143 143
Advisory Fees Paid, Amount $ 37,731,195          
Investment Company, Portfolio Turnover 90.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks98.9%Biotechnology12%
Short-Term Investments4.1%Semiconductors and Semiconductor Equipment8%
Other Assets and Liabilities(3.0)%Software8%
 Electronic Equipment, Instruments and Components6%
 Aerospace and Defense6%
          
C000017052 [Member]            
Shareholder Report [Line Items]            
Fund Name Small Cap Growth Fund          
Class Name C Class          
Trading Symbol ANOCX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Small Cap Growth Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
C Class$2252.13%
          
Expenses Paid, Amount $ 225          
Expense Ratio, Percent 2.13%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Small Cap Growth Fund C Class returned 10.86% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund’s performance compared to the Russell 2000 Growth Index.
•
Stock selection in the health care sector contributed the most to the portfolio’s relative performance. While the portfolio took an underweight position in biotechnology, it had key holdings in companies like Natera, a genetic testing firm that was a portfolio-only stock. After a strong third quarter, the company significantly increased its guidance for the year.
•
Consumer discretionary was another important contributor due to stock selection. Owning Duolingo was key as the learning application company converted more freemium users to paid subscriptions and increased sales of its higher-priced family plans. In the hotels, restaurants and leisure industry, not owning companies like Sweetgreen, Shake Shack and Six Flags Entertainment helped.
•
The industrials sector acted as the leading detractor, largely due to stock selection. The portfolio did not own several key stocks in the electrical equipment industry, including Bloom Energy and Nextracker, which were part of the Russell 2000 Growth Index. Bloom has benefited from the artificial intelligence trend, which has fueled demand for its onsite power generation solutions.
•
Information technology was another notable detractor from the portfolio’s relative performance. In particular, our position in the semiconductors and semiconductor equipment industry was hurt by stock selection. We didn’t own Rigetti Computing, which was up on the potential for quantum computing solutions.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
October 31, 2015 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 Year10 Year
C Class10.86%6.54%10.92%
Regulatory Index
Russell 300020.81%16.74%14.08%
Performance Index
Russell 2000 Growth18.81%8.94%9.65%
          
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 4,937,399,531 $ 4,937,399,531 $ 4,937,399,531 $ 4,937,399,531 $ 4,937,399,531 $ 4,937,399,531
Holdings Count | holding 143 143 143 143 143 143
Advisory Fees Paid, Amount $ 37,731,195          
Investment Company, Portfolio Turnover 90.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks98.9%Biotechnology12%
Short-Term Investments4.1%Semiconductors and Semiconductor Equipment8%
Other Assets and Liabilities(3.0)%Software8%
 Electronic Equipment, Instruments and Components6%
 Aerospace and Defense6%
          
C000055516 [Member]            
Shareholder Report [Line Items]            
Fund Name Small Cap Growth Fund          
Class Name R Class          
Trading Symbol ANORX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Small Cap Growth Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
R Class$1721.63%
          
Expenses Paid, Amount $ 172          
Expense Ratio, Percent 1.63%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Small Cap Growth Fund R Class returned 11.40% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund’s performance compared to the Russell 2000 Growth Index.
•
Stock selection in the health care sector contributed the most to the portfolio’s relative performance. While the portfolio took an underweight position in biotechnology, it had key holdings in companies like Natera, a genetic testing firm that was a portfolio-only stock. After a strong third quarter, the company significantly increased its guidance for the year.
•
Consumer discretionary was another important contributor due to stock selection. Owning Duolingo was key as the learning application company converted more freemium users to paid subscriptions and increased sales of its higher-priced family plans. In the hotels, restaurants and leisure industry, not owning companies like Sweetgreen, Shake Shack and Six Flags Entertainment helped.
•
The industrials sector acted as the leading detractor, largely due to stock selection. The portfolio did not own several key stocks in the electrical equipment industry, including Bloom Energy and Nextracker, which were part of the Russell 2000 Growth Index. Bloom has benefited from the artificial intelligence trend, which has fueled demand for its onsite power generation solutions.
•
Information technology was another notable detractor from the portfolio’s relative performance. In particular, our position in the semiconductors and semiconductor equipment industry was hurt by stock selection. We didn’t own Rigetti Computing, which was up on the potential for quantum computing solutions.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
October 31, 2015 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 Year10 Year
R Class11.40%7.07%11.47%
Regulatory Index
Russell 300020.81%16.74%14.08%
Performance Index
Russell 2000 Growth18.81%8.94%9.65%
          
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 4,937,399,531 $ 4,937,399,531 $ 4,937,399,531 $ 4,937,399,531 $ 4,937,399,531 $ 4,937,399,531
Holdings Count | holding 143 143 143 143 143 143
Advisory Fees Paid, Amount $ 37,731,195          
Investment Company, Portfolio Turnover 90.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks98.9%Biotechnology12%
Short-Term Investments4.1%Semiconductors and Semiconductor Equipment8%
Other Assets and Liabilities(3.0)%Software8%
 Electronic Equipment, Instruments and Components6%
 Aerospace and Defense6%
          
C000189735 [Member]            
Shareholder Report [Line Items]            
Fund Name Small Cap Growth Fund          
Class Name R5 Class          
Trading Symbol ANOGX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Small Cap Growth Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
R5 Class$990.93%
          
Expenses Paid, Amount $ 99          
Expense Ratio, Percent 0.93%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Small Cap Growth Fund R5 Class returned 12.16% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund’s performance compared to the Russell 2000 Growth Index.
•
Stock selection in the health care sector contributed the most to the portfolio’s relative performance. While the portfolio took an underweight position in biotechnology, it had key holdings in companies like Natera, a genetic testing firm that was a portfolio-only stock. After a strong third quarter, the company significantly increased its guidance for the year.
•
Consumer discretionary was another important contributor due to stock selection. Owning Duolingo was key as the learning application company converted more freemium users to paid subscriptions and increased sales of its higher-priced family plans. In the hotels, restaurants and leisure industry, not owning companies like Sweetgreen, Shake Shack and Six Flags Entertainment helped.
•
The industrials sector acted as the leading detractor, largely due to stock selection. The portfolio did not own several key stocks in the electrical equipment industry, including Bloom Energy and Nextracker, which were part of the Russell 2000 Growth Index. Bloom has benefited from the artificial intelligence trend, which has fueled demand for its onsite power generation solutions.
•
Information technology was another notable detractor from the portfolio’s relative performance. In particular, our position in the semiconductors and semiconductor equipment industry was hurt by stock selection. We didn’t own Rigetti Computing, which was up on the potential for quantum computing solutions.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
April 10, 2017 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 YearSince InceptionInception Date
R5 Class12.16%7.83%12.60%4/10/17
Regulatory Index
Russell 300020.81%16.74%14.50%—
Performance Index
Russell 2000 Growth18.81%8.94%9.65%—
          
Performance Inception Date           Apr. 10, 2017
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 4,937,399,531 $ 4,937,399,531 $ 4,937,399,531 $ 4,937,399,531 $ 4,937,399,531 $ 4,937,399,531
Holdings Count | holding 143 143 143 143 143 143
Advisory Fees Paid, Amount $ 37,731,195          
Investment Company, Portfolio Turnover 90.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks98.9%Biotechnology12%
Short-Term Investments4.1%Semiconductors and Semiconductor Equipment8%
Other Assets and Liabilities(3.0)%Software8%
 Electronic Equipment, Instruments and Components6%
 Aerospace and Defense6%
          
C000131596 [Member]            
Shareholder Report [Line Items]            
Fund Name Small Cap Growth Fund          
Class Name R6 Class          
Trading Symbol ANODX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Small Cap Growth Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
R6 Class$830.78%
          
Expenses Paid, Amount $ 83          
Expense Ratio, Percent 0.78%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Small Cap Growth Fund R6 Class returned 12.31% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund’s performance compared to the Russell 2000 Growth Index.
•
Stock selection in the health care sector contributed the most to the portfolio’s relative performance. While the portfolio took an underweight position in biotechnology, it had key holdings in companies like Natera, a genetic testing firm that was a portfolio-only stock. After a strong third quarter, the company significantly increased its guidance for the year.
•
Consumer discretionary was another important contributor due to stock selection. Owning Duolingo was key as the learning application company converted more freemium users to paid subscriptions and increased sales of its higher-priced family plans. In the hotels, restaurants and leisure industry, not owning companies like Sweetgreen, Shake Shack and Six Flags Entertainment helped.
•
The industrials sector acted as the leading detractor, largely due to stock selection. The portfolio did not own several key stocks in the electrical equipment industry, including Bloom Energy and Nextracker, which were part of the Russell 2000 Growth Index. Bloom has benefited from the artificial intelligence trend, which has fueled demand for its onsite power generation solutions.
•
Information technology was another notable detractor from the portfolio’s relative performance. In particular, our position in the semiconductors and semiconductor equipment industry was hurt by stock selection. We didn’t own Rigetti Computing, which was up on the potential for quantum computing solutions.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
October 31, 2015 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 Year10 Year
R6 Class12.31%7.99%12.41%
Regulatory Index
Russell 300020.81%16.74%14.08%
Performance Index
Russell 2000 Growth18.81%8.94%9.65%
          
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 4,937,399,531 $ 4,937,399,531 $ 4,937,399,531 $ 4,937,399,531 $ 4,937,399,531 $ 4,937,399,531
Holdings Count | holding 143 143 143 143 143 143
Advisory Fees Paid, Amount $ 37,731,195          
Investment Company, Portfolio Turnover 90.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks98.9%Biotechnology12%
Short-Term Investments4.1%Semiconductors and Semiconductor Equipment8%
Other Assets and Liabilities(3.0)%Software8%
 Electronic Equipment, Instruments and Components6%
 Aerospace and Defense6%
          
C000212512 [Member]            
Shareholder Report [Line Items]            
Fund Name Small Cap Growth Fund          
Class Name G Class          
Trading Symbol ANOHX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Small Cap Growth Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
G Class$00.00%
          
Expenses Paid, Amount $ 0          
Expense Ratio, Percent 0.00%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Small Cap Growth Fund G Class returned 13.19% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund’s performance compared to the Russell 2000 Growth Index.
•
Stock selection in the health care sector contributed the most to the portfolio’s relative performance. While the portfolio took an underweight position in biotechnology, it had key holdings in companies like Natera, a genetic testing firm that was a portfolio-only stock. After a strong third quarter, the company significantly increased its guidance for the year.
•
Consumer discretionary was another important contributor due to stock selection. Owning Duolingo was key as the learning application company converted more freemium users to paid subscriptions and increased sales of its higher-priced family plans. In the hotels, restaurants and leisure industry, not owning companies like Sweetgreen, Shake Shack and Six Flags Entertainment helped.
•
The industrials sector acted as the leading detractor, largely due to stock selection. The portfolio did not own several key stocks in the electrical equipment industry, including Bloom Energy and Nextracker, which were part of the Russell 2000 Growth Index. Bloom has benefited from the artificial intelligence trend, which has fueled demand for its onsite power generation solutions.
•
Information technology was another notable detractor from the portfolio’s relative performance. In particular, our position in the semiconductors and semiconductor equipment industry was hurt by stock selection. We didn’t own Rigetti Computing, which was up on the potential for quantum computing solutions.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
April 1, 2019 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 YearSince InceptionInception Date
G Class13.19%8.85%12.37%4/1/19
Regulatory Index
Russell 300020.81%16.74%15.19%—
Performance Index
Russell 2000 Growth18.81%8.94%8.84%—
          
Performance Inception Date         Apr. 01, 2019  
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 4,937,399,531 $ 4,937,399,531 $ 4,937,399,531 $ 4,937,399,531 $ 4,937,399,531 $ 4,937,399,531
Holdings Count | holding 143 143 143 143 143 143
Advisory Fees Paid, Amount $ 37,731,195          
Investment Company, Portfolio Turnover 90.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks98.9%Biotechnology12%
Short-Term Investments4.1%Semiconductors and Semiconductor Equipment8%
Other Assets and Liabilities(3.0)%Software8%
 Electronic Equipment, Instruments and Components6%
 Aerospace and Defense6%
          
C000017060 [Member]            
Shareholder Report [Line Items]            
Fund Name Ultra Fund          
Class Name Investor Class          
Trading Symbol TWCUX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Ultra Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Investor Class$990.88%
          
Expenses Paid, Amount $ 99          
Expense Ratio, Percent 0.88%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Ultra Fund Investor Class returned 24.09% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund’s performance compared to the Russell 1000 Growth Index.
•
Stock selection in the communication services sector contributed most to relative performance. An overweight to internet search giant Alphabet, parent of Google and YouTube, was a leading contributor to relative results. Here, too, the company’s results benefited from artificial intelligence (AI)-enhanced advertising placement and content creation.
•
Among individual contributors, a notable source of strength was a position in AI chip giant NVIDIA. The company’s chips are central to the AI revolution, and have helped it lay claim to being the world’s most valauble company as measured by market capitalization at the end of October 2025.
•
In information technology, semiconductors and semiconductor equipment and software stocks hurt relative results. Several of the leading detractors are explained by their exposure to AI. The top relative detractor was AI chipmaker Broadcom, to which we had limited exposure. It also hurt to be underrepresented in shares of AI software and consulting firm Palantir Technologies.
•
Stock selection in the consumer discretionary sector detracted from relative performance. It hurt to have exposure to shares of select hotels, restaurants and leisure companies, as well as those of textiles, apparel and luxury goods makers. In general, these stocks suffered from weaker spending by lower-income and price-sensitive consumers.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
October 31, 2015 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 Year10 Year
Investor Class24.09%16.17%17.24%
Regulatory Index
Russell 100021.14%17.05%14.39%
Performance Index
Russell 1000 Growth30.52%19.24%18.28%
          
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 28,204,062,455 $ 28,204,062,455 $ 28,204,062,455 $ 28,204,062,455 $ 28,204,062,455 $ 28,204,062,455
Holdings Count | holding 64 64 64 64 64 64
Advisory Fees Paid, Amount $ 214,875,793          
Investment Company, Portfolio Turnover 15.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks99.9%Semiconductors and Semiconductor Equipment23%
Rights0.0%Software16%
Short-Term Investments0.1%Interactive Media and Services13%
Other Assets and Liabilities0.0%Technology Hardware, Storage and Peripherals9%
 Broadline Retail7%
          
C000017062 [Member]            
Shareholder Report [Line Items]            
Fund Name Ultra Fund          
Class Name I Class          
Trading Symbol TWUIX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Ultra Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
I Class$760.68%
          
Expenses Paid, Amount $ 76          
Expense Ratio, Percent 0.68%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Ultra Fund I Class returned 24.35% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund’s performance compared to the Russell 1000 Growth Index.
•
Stock selection in the communication services sector contributed most to relative performance. An overweight to internet search giant Alphabet, parent of Google and YouTube, was a leading contributor to relative results. Here, too, the company’s results benefited from artificial intelligence (AI)-enhanced advertising placement and content creation.
•
Among individual contributors, a notable source of strength was a position in AI chip giant NVIDIA. The company’s chips are central to the AI revolution, and have helped it lay claim to being the world’s most valauble company as measured by market capitalization at the end of October 2025.
•
In information technology, semiconductors and semiconductor equipment and software stocks hurt relative results. Several of the leading detractors are explained by their exposure to AI. The top relative detractor was AI chipmaker Broadcom, to which we had limited exposure. It also hurt to be underrepresented in shares of AI software and consulting firm Palantir Technologies.
•
Stock selection in the consumer discretionary sector detracted from relative performance. It hurt to have exposure to shares of select hotels, restaurants and leisure companies, as well as those of textiles, apparel and luxury goods makers. In general, these stocks suffered from weaker spending by lower-income and price-sensitive consumers.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
October 31, 2015 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 Year10 Year
I Class24.35%16.41%17.47%
Regulatory Index
Russell 100021.14%17.05%14.39%
Performance Index
Russell 1000 Growth30.52%19.24%18.28%
          
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 28,204,062,455 $ 28,204,062,455 $ 28,204,062,455 $ 28,204,062,455 $ 28,204,062,455 $ 28,204,062,455
Holdings Count | holding 64 64 64 64 64 64
Advisory Fees Paid, Amount $ 214,875,793          
Investment Company, Portfolio Turnover 15.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks99.9%Semiconductors and Semiconductor Equipment23%
Rights0.0%Software16%
Short-Term Investments0.1%Interactive Media and Services13%
Other Assets and Liabilities0.0%Technology Hardware, Storage and Peripherals9%
 Broadline Retail7%
          
C000189740 [Member]            
Shareholder Report [Line Items]            
Fund Name Ultra Fund          
Class Name Y Class          
Trading Symbol AULYX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Ultra Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Y Class$600.53%
          
Expenses Paid, Amount $ 60          
Expense Ratio, Percent 0.53%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Ultra Fund Y Class returned 24.53% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund’s performance compared to the Russell 1000 Growth Index.
•
Stock selection in the communication services sector contributed most to relative performance. An overweight to internet search giant Alphabet, parent of Google and YouTube, was a leading contributor to relative results. Here, too, the company’s results benefited from artificial intelligence (AI)-enhanced advertising placement and content creation.
•
Among individual contributors, a notable source of strength was a position in AI chip giant NVIDIA. The company’s chips are central to the AI revolution, and have helped it lay claim to being the world’s most valauble company as measured by market capitalization at the end of October 2025.
•
In information technology, semiconductors and semiconductor equipment and software stocks hurt relative results. Several of the leading detractors are explained by their exposure to AI. The top relative detractor was AI chipmaker Broadcom, to which we had limited exposure. It also hurt to be underrepresented in shares of AI software and consulting firm Palantir Technologies.
•
Stock selection in the consumer discretionary sector detracted from relative performance. It hurt to have exposure to shares of select hotels, restaurants and leisure companies, as well as those of textiles, apparel and luxury goods makers. In general, these stocks suffered from weaker spending by lower-income and price-sensitive consumers.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
April 10, 2017 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 YearSince InceptionInception Date
Y Class24.53%16.58%19.28%4/10/17
Regulatory Index
Russell 100021.14%17.05%14.89%—
Performance Index
Russell 1000 Growth30.52%19.24%19.68%—
          
Performance Inception Date           Apr. 10, 2017
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 28,204,062,455 $ 28,204,062,455 $ 28,204,062,455 $ 28,204,062,455 $ 28,204,062,455 $ 28,204,062,455
Holdings Count | holding 64 64 64 64 64 64
Advisory Fees Paid, Amount $ 214,875,793          
Investment Company, Portfolio Turnover 15.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks99.9%Semiconductors and Semiconductor Equipment23%
Rights0.0%Software16%
Short-Term Investments0.1%Interactive Media and Services13%
Other Assets and Liabilities0.0%Technology Hardware, Storage and Peripherals9%
 Broadline Retail7%
          
C000017061 [Member]            
Shareholder Report [Line Items]            
Fund Name Ultra Fund          
Class Name A Class          
Trading Symbol TWUAX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Ultra Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
A Class$1261.13%
          
Expenses Paid, Amount $ 126          
Expense Ratio, Percent 1.13%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Ultra Fund A Class returned 23.78% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund’s performance compared to the Russell 1000 Growth Index.
•
Stock selection in the communication services sector contributed most to relative performance. An overweight to internet search giant Alphabet, parent of Google and YouTube, was a leading contributor to relative results. Here, too, the company’s results benefited from artificial intelligence (AI)-enhanced advertising placement and content creation.
•
Among individual contributors, a notable source of strength was a position in AI chip giant NVIDIA. The company’s chips are central to the AI revolution, and have helped it lay claim to being the world’s most valauble company as measured by market capitalization at the end of October 2025.
•
In information technology, semiconductors and semiconductor equipment and software stocks hurt relative results. Several of the leading detractors are explained by their exposure to AI. The top relative detractor was AI chipmaker Broadcom, to which we had limited exposure. It also hurt to be underrepresented in shares of AI software and consulting firm Palantir Technologies.
•
Stock selection in the consumer discretionary sector detracted from relative performance. It hurt to have exposure to shares of select hotels, restaurants and leisure companies, as well as those of textiles, apparel and luxury goods makers. In general, these stocks suffered from weaker spending by lower-income and price-sensitive consumers.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
October 31, 2015 through October 31, 2025
The initial investment is adjusted to reflect the maximum initial sales charge.
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 Year10 Year
A Class23.78%15.88%16.95%
A Class - with sales charge16.67%14.52%16.26%
Regulatory Index
Russell 100021.14%17.05%14.39%
Performance Index
Russell 1000 Growth30.52%19.24%18.28%
          
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 28,204,062,455 $ 28,204,062,455 $ 28,204,062,455 $ 28,204,062,455 $ 28,204,062,455 $ 28,204,062,455
Holdings Count | holding 64 64 64 64 64 64
Advisory Fees Paid, Amount $ 214,875,793          
Investment Company, Portfolio Turnover 15.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks99.9%Semiconductors and Semiconductor Equipment23%
Rights0.0%Software16%
Short-Term Investments0.1%Interactive Media and Services13%
Other Assets and Liabilities0.0%Technology Hardware, Storage and Peripherals9%
 Broadline Retail7%
          
C000017063 [Member]            
Shareholder Report [Line Items]            
Fund Name Ultra Fund          
Class Name C Class          
Trading Symbol TWCCX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Ultra Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
C Class$2091.88%
          
Expenses Paid, Amount $ 209          
Expense Ratio, Percent 1.88%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Ultra Fund C Class returned 22.86% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund’s performance compared to the Russell 1000 Growth Index.
•
Stock selection in the communication services sector contributed most to relative performance. An overweight to internet search giant Alphabet, parent of Google and YouTube, was a leading contributor to relative results. Here, too, the company’s results benefited from artificial intelligence (AI)-enhanced advertising placement and content creation.
•
Among individual contributors, a notable source of strength was a position in AI chip giant NVIDIA. The company’s chips are central to the AI revolution, and have helped it lay claim to being the world’s most valauble company as measured by market capitalization at the end of October 2025.
•
In information technology, semiconductors and semiconductor equipment and software stocks hurt relative results. Several of the leading detractors are explained by their exposure to AI. The top relative detractor was AI chipmaker Broadcom, to which we had limited exposure. It also hurt to be underrepresented in shares of AI software and consulting firm Palantir Technologies.
•
Stock selection in the consumer discretionary sector detracted from relative performance. It hurt to have exposure to shares of select hotels, restaurants and leisure companies, as well as those of textiles, apparel and luxury goods makers. In general, these stocks suffered from weaker spending by lower-income and price-sensitive consumers.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
October 31, 2015 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 Year10 Year
C Class22.86%15.02%16.08%
Regulatory Index
Russell 100021.14%17.05%14.39%
Performance Index
Russell 1000 Growth30.52%19.24%18.28%
          
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 28,204,062,455 $ 28,204,062,455 $ 28,204,062,455 $ 28,204,062,455 $ 28,204,062,455 $ 28,204,062,455
Holdings Count | holding 64 64 64 64 64 64
Advisory Fees Paid, Amount $ 214,875,793          
Investment Company, Portfolio Turnover 15.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks99.9%Semiconductors and Semiconductor Equipment23%
Rights0.0%Software16%
Short-Term Investments0.1%Interactive Media and Services13%
Other Assets and Liabilities0.0%Technology Hardware, Storage and Peripherals9%
 Broadline Retail7%
          
C000017064 [Member]            
Shareholder Report [Line Items]            
Fund Name Ultra Fund          
Class Name R Class          
Trading Symbol AULRX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Ultra Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
R Class$1541.38%
          
Expenses Paid, Amount $ 154          
Expense Ratio, Percent 1.38%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Ultra Fund R Class returned 23.48% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund’s performance compared to the Russell 1000 Growth Index.
•
Stock selection in the communication services sector contributed most to relative performance. An overweight to internet search giant Alphabet, parent of Google and YouTube, was a leading contributor to relative results. Here, too, the company’s results benefited from artificial intelligence (AI)-enhanced advertising placement and content creation.
•
Among individual contributors, a notable source of strength was a position in AI chip giant NVIDIA. The company’s chips are central to the AI revolution, and have helped it lay claim to being the world’s most valauble company as measured by market capitalization at the end of October 2025.
•
In information technology, semiconductors and semiconductor equipment and software stocks hurt relative results. Several of the leading detractors are explained by their exposure to AI. The top relative detractor was AI chipmaker Broadcom, to which we had limited exposure. It also hurt to be underrepresented in shares of AI software and consulting firm Palantir Technologies.
•
Stock selection in the consumer discretionary sector detracted from relative performance. It hurt to have exposure to shares of select hotels, restaurants and leisure companies, as well as those of textiles, apparel and luxury goods makers. In general, these stocks suffered from weaker spending by lower-income and price-sensitive consumers.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
October 31, 2015 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 Year10 Year
R Class23.48%15.59%16.65%
Regulatory Index
Russell 100021.14%17.05%14.39%
Performance Index
Russell 1000 Growth30.52%19.24%18.28%
          
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 28,204,062,455 $ 28,204,062,455 $ 28,204,062,455 $ 28,204,062,455 $ 28,204,062,455 $ 28,204,062,455
Holdings Count | holding 64 64 64 64 64 64
Advisory Fees Paid, Amount $ 214,875,793          
Investment Company, Portfolio Turnover 15.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks99.9%Semiconductors and Semiconductor Equipment23%
Rights0.0%Software16%
Short-Term Investments0.1%Interactive Media and Services13%
Other Assets and Liabilities0.0%Technology Hardware, Storage and Peripherals9%
 Broadline Retail7%
          
C000189739 [Member]            
Shareholder Report [Line Items]            
Fund Name Ultra Fund          
Class Name R5 Class          
Trading Symbol AULGX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Ultra Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
R5 Class$760.68%
          
Expenses Paid, Amount $ 76          
Expense Ratio, Percent 0.68%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Ultra Fund R5 Class returned 24.34% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund’s performance compared to the Russell 1000 Growth Index.
•
Stock selection in the communication services sector contributed most to relative performance. An overweight to internet search giant Alphabet, parent of Google and YouTube, was a leading contributor to relative results. Here, too, the company’s results benefited from artificial intelligence (AI)-enhanced advertising placement and content creation.
•
Among individual contributors, a notable source of strength was a position in AI chip giant NVIDIA. The company’s chips are central to the AI revolution, and have helped it lay claim to being the world’s most valauble company as measured by market capitalization at the end of October 2025.
•
In information technology, semiconductors and semiconductor equipment and software stocks hurt relative results. Several of the leading detractors are explained by their exposure to AI. The top relative detractor was AI chipmaker Broadcom, to which we had limited exposure. It also hurt to be underrepresented in shares of AI software and consulting firm Palantir Technologies.
•
Stock selection in the consumer discretionary sector detracted from relative performance. It hurt to have exposure to shares of select hotels, restaurants and leisure companies, as well as those of textiles, apparel and luxury goods makers. In general, these stocks suffered from weaker spending by lower-income and price-sensitive consumers.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
April 10, 2017 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 YearSince InceptionInception Date
R5 Class24.34%16.41%19.10%4/10/17
Regulatory Index
Russell 100021.14%17.05%14.89%—
Performance Index
Russell 1000 Growth30.52%19.24%19.68%—
          
Performance Inception Date           Apr. 10, 2017
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 28,204,062,455 $ 28,204,062,455 $ 28,204,062,455 $ 28,204,062,455 $ 28,204,062,455 $ 28,204,062,455
Holdings Count | holding 64 64 64 64 64 64
Advisory Fees Paid, Amount $ 214,875,793          
Investment Company, Portfolio Turnover 15.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks99.9%Semiconductors and Semiconductor Equipment23%
Rights0.0%Software16%
Short-Term Investments0.1%Interactive Media and Services13%
Other Assets and Liabilities0.0%Technology Hardware, Storage and Peripherals9%
 Broadline Retail7%
          
C000131598 [Member]            
Shareholder Report [Line Items]            
Fund Name Ultra Fund          
Class Name R6 Class          
Trading Symbol AULDX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Ultra Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
R6 Class$590.53%
          
Expenses Paid, Amount $ 59          
Expense Ratio, Percent 0.53%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Ultra Fund R6 Class returned 24.52% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund’s performance compared to the Russell 1000 Growth Index.
•
Stock selection in the communication services sector contributed most to relative performance. An overweight to internet search giant Alphabet, parent of Google and YouTube, was a leading contributor to relative results. Here, too, the company’s results benefited from artificial intelligence (AI)-enhanced advertising placement and content creation.
•
Among individual contributors, a notable source of strength was a position in AI chip giant NVIDIA. The company’s chips are central to the AI revolution, and have helped it lay claim to being the world’s most valauble company as measured by market capitalization at the end of October 2025.
•
In information technology, semiconductors and semiconductor equipment and software stocks hurt relative results. Several of the leading detractors are explained by their exposure to AI. The top relative detractor was AI chipmaker Broadcom, to which we had limited exposure. It also hurt to be underrepresented in shares of AI software and consulting firm Palantir Technologies.
•
Stock selection in the consumer discretionary sector detracted from relative performance. It hurt to have exposure to shares of select hotels, restaurants and leisure companies, as well as those of textiles, apparel and luxury goods makers. In general, these stocks suffered from weaker spending by lower-income and price-sensitive consumers.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
October 31, 2015 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 Year10 Year
R6 Class24.52%16.58%17.65%
Regulatory Index
Russell 100021.14%17.05%14.39%
Performance Index
Russell 1000 Growth30.52%19.24%18.28%
          
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 28,204,062,455 $ 28,204,062,455 $ 28,204,062,455 $ 28,204,062,455 $ 28,204,062,455 $ 28,204,062,455
Holdings Count | holding 64 64 64 64 64 64
Advisory Fees Paid, Amount $ 214,875,793          
Investment Company, Portfolio Turnover 15.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks99.9%Semiconductors and Semiconductor Equipment23%
Rights0.0%Software16%
Short-Term Investments0.1%Interactive Media and Services13%
Other Assets and Liabilities0.0%Technology Hardware, Storage and Peripherals9%
 Broadline Retail7%
          
C000214991 [Member]            
Shareholder Report [Line Items]            
Fund Name Ultra Fund          
Class Name G Class          
Trading Symbol AULNX          
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Ultra Fund for the period of November 1, 2024 to October 31, 2025.          
Shareholder Report Annual or Semi-Annual annual shareholder report          
Additional Information [Text Block] You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.          
Additional Information Phone Number 1-800-345-2021          
Additional Information Website americancentury.com/docs          
Expenses [Text Block]
What were the fund costs for the last year? (based on a hypothetical $10,000 investment)
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
G Class$00.00%
          
Expenses Paid, Amount $ 0          
Expense Ratio, Percent 0.00%          
Factors Affecting Performance [Text Block]
What were the key factors that affected the fund’s performance?
Ultra Fund G Class returned 25.20% for the reporting period ended October 31, 2025.
The fund seeks long-term capital growth. The commentary below refers to the fund’s performance compared to the Russell 1000 Growth Index.
•
Stock selection in the communication services sector contributed most to relative performance. An overweight to internet search giant Alphabet, parent of Google and YouTube, was a leading contributor to relative results. Here, too, the company’s results benefited from artificial intelligence (AI)-enhanced advertising placement and content creation.
•
Among individual contributors, a notable source of strength was a position in AI chip giant NVIDIA. The company’s chips are central to the AI revolution, and have helped it lay claim to being the world’s most valauble company as measured by market capitalization at the end of October 2025.
•
In information technology, semiconductors and semiconductor equipment and software stocks hurt relative results. Several of the leading detractors are explained by their exposure to AI. The top relative detractor was AI chipmaker Broadcom, to which we had limited exposure. It also hurt to be underrepresented in shares of AI software and consulting firm Palantir Technologies.
•
Stock selection in the consumer discretionary sector detracted from relative performance. It hurt to have exposure to shares of select hotels, restaurants and leisure companies, as well as those of textiles, apparel and luxury goods makers. In general, these stocks suffered from weaker spending by lower-income and price-sensitive consumers.
          
Line Graph [Table Text Block]
Cumulative Performance (based on an initial $10,000 investment)
August 1, 2019 through October 31, 2025
9
          
Average Annual Return [Table Text Block]
Average Annual Total Returns
1 Year5 YearSince InceptionInception Date
G Class25.20%17.25%20.14%8/1/19
Regulatory Index
Russell 100021.14%17.05%15.84%—
Performance Index
Russell 1000 Growth30.52%19.24%20.41%—
          
Performance Inception Date       Aug. 01, 2019    
No Deduction of Taxes [Text Block] The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.          
Updated Performance Information Location [Text Block] Visit americancentury.com for more recent performance information.          
Net Assets $ 28,204,062,455 $ 28,204,062,455 $ 28,204,062,455 $ 28,204,062,455 $ 28,204,062,455 $ 28,204,062,455
Holdings Count | holding 64 64 64 64 64 64
Advisory Fees Paid, Amount $ 214,875,793          
Investment Company, Portfolio Turnover 15.00%          
Holdings [Text Block]
Fund Holdings
Types of Investments in Portfolio (as a % of net assets)
Top Five Industries (as a % of net assets)
Common Stocks99.9%Semiconductors and Semiconductor Equipment23%
Rights0.0%Software16%
Short-Term Investments0.1%Interactive Media and Services13%
Other Assets and Liabilities0.0%Technology Hardware, Storage and Peripherals9%
 Broadline Retail7%