Debt - Janus Living Credit Facilities, Bank Line of Credit and Term Loan (Details)		1 Months Ended	6 Months Ended
	Mar. 23, 2026 USD ($) renewal_option	Oct. 31, 2025	Jun. 30, 2026 USD ($) derivative_held renewal_option	Mar. 31, 2026 USD ($)	Feb. 28, 2026 USD ($)	Dec. 31, 2025 USD ($)	Mar. 01, 2024 derivative_held	Aug. 31, 2022 derivative_held	Apr. 30, 2022 derivative_held
Interest rate swap instruments | Designated as Hedging Instrument
Debt Instrument
Number of interest-rate contracts held | derivative_held			2					2
Interest rate swap instruments | Designated as Hedging Instrument | Cash Flow Hedging
Debt Instrument
Number of interest-rate contracts held | derivative_held									2
Janus Living Credit Facilities | Bank Line  of Credit
Debt Instrument
Debt issuance costs, net			$ 2,000,000
Debt instrument, covenant debt to assets (as a percent)	60.00%
Debt instrument, covenant secured debt to assets (as a percent)	40.00%
Debt instrument, covenant unsecured debt to unencumbered assets (as a percent)	60.00%
Debt instrument, covenant minimum fixed charge coverage ratio	1.5
Debt instrument, covenant net worth, minimum	$ 2,040,000,000.00
Percentage of net proceeds received	75.00%
Minimum unsecured interest coverage ratio	1.75
Term Loan Agreement
Debt Instrument
Line of credit facility, maximum borrowing capacity			1,500,000,000	$ 2,000,000,000.0	$ 1,500,000,000
Bank line of credit and commercial paper			$ 1,250,000,000			$ 1,250,000,000
Debt instrument, covenant debt to assets (as a percent)			60.00%
Debt instrument, covenant secured debt to assets (as a percent)			40.00%
Debt instrument, covenant unsecured debt to unencumbered assets (as a percent)			60.00%
Debt instrument, covenant minimum fixed charge coverage ratio			1.5
Debt instrument, covenant net worth, minimum			$ 7,700,000,000
Unsecured Term Loan
Debt Instrument
Aggregate principal amount			750,000,000
Unused borrowing capacity, amount			$ 750,000,000
2029 Term Loan | Unsecured Term Loan
Debt Instrument
Debt instrument, basis spread on variable rate (as a percent)			0.85%
Debt Instrument, Variable Interest Rate, Type [Extensible Enumeration]			Secured Overnight Financing Rate (SOFR) [Member]
2029 Term Loan | Senior Unsecured Term Loan
Debt Instrument
Interest rate, effective (as a percent)			4.56%
2031 Term Loan | Unsecured Term Loan
Debt Instrument
Debt instrument, basis spread on variable rate (as a percent)			0.80%
2028 Term Loan | Senior Unsecured Term Loan
Debt Instrument
Aggregate principal amount			$ 400,000,000
Debt instrument, basis spread on variable rate (as a percent)		0.10%	0.90%
2028 Term Loan | Senior Unsecured Term Loan | Minimum
Debt Instrument
Debt instrument, basis spread on variable rate (as a percent)			0.85%
2028 Term Loan | Senior Unsecured Term Loan | Maximum
Debt Instrument
Debt instrument, basis spread on variable rate (as a percent)			1.65%
2028 Term Loan | Senior Unsecured Term Loan | Interest rate swap instruments | Designated as Hedging Instrument | Cash Flow Hedging
Debt Instrument
Number of interest-rate contracts held | derivative_held			3				3
Revolving Credit Facility | Bank Line  of Credit
Debt Instrument
Line of credit facility, maximum borrowing capacity			$ 3,000,000,000.0
Number of extensions | renewal_option			2
Length of debt instrument extension period (in months)			6 months
Debt instrument, basis spread on variable rate (as a percent)		0.10%
Debt instrument, facility fee (as a percent)			0.15%
Bank line of credit and commercial paper			$ 0			$ 0
Line of credit facility additional aggregate amount, maximum			$ 750,000,000
Revolving Credit Facility | Bank Line  of Credit | Variable Rate Component One
Debt Instrument
Debt instrument, basis spread on variable rate (as a percent)			0.78%
Revolving Credit Facility | Janus Living Credit Facilities | Bank Line  of Credit
Debt Instrument
Line of credit facility, maximum borrowing capacity	$ 500,000,000
Debt accordion feature	$ 1,500,000,000
Number of extensions | renewal_option	2
Length of debt instrument extension period (in months)	6 months
Debt instrument, basis spread on variable rate (as a percent)			1.05%
Debt instrument, facility fee (as a percent)			0.15%
Bank line of credit and commercial paper			$ 0
Delayed Draw Term Loan (DDTL) | Janus Living Credit Facilities | Bank Line  of Credit
Debt Instrument
Aggregate principal amount	$ 100,000,000
Debt instrument, basis spread on variable rate (as a percent)			1.10%
Bank line of credit and commercial paper			$ 0
2027 Term Loan Facilities | Term Loan Agreement | Interest rate swap instruments
Debt Instrument
Interest rate, effective (as a percent)			3.65%
2027 Term Loan Facilities | Term Loan Agreement | Bank Line  of Credit
Debt Instrument
Aggregate principal amount			$ 500,000,000
Number of extensions | renewal_option			1
Length of debt instrument extension period (in months)			1 year
Debt instrument, basis spread on variable rate (as a percent)		0.10%	0.84%
Debt Instrument, Variable Interest Rate, Type [Extensible Enumeration]			Secured Overnight Financing Rate (SOFR) [Member]
Debt Instrument, interest rate, reduction available for sustainability metrics (as a percent)			0.0001
2028 Term Loan Facilities | Term Loan Agreement | Interest rate swap instruments
Debt Instrument
Interest rate, effective (as a percent)			4.35%
2027 Term Loan Facilities One | Term Loan Agreement | Bank Line  of Credit
Debt Instrument
Line of credit facility, maximum borrowing capacity			$ 250,000,000
2027 Term Loan Facilities Two | Term Loan Agreement | Bank Line  of Credit
Debt Instrument
Line of credit facility, maximum borrowing capacity			250,000,000
2031 Term Loan Facility | Unsecured Delayed Draw Term Loan
Debt Instrument
Aggregate principal amount				$ 400,000,000
Bank line of credit and commercial paper			$ 0
Debt instrument, term (in months)			5 years