Fair Value Disclosures - Investments in Certain Entities Calculate Net Asset Value per Share (Detail) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
Sep. 30, 2026	Dec. 31, 2025
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total Unfunded Commitments	$ 2,216	$ 2,356
Fair Value Measured at NAV per share [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	3,513	2,858
Hedge Funds/Funds of Hedge Funds/Other [Member] \| Consolidated Variable Interest Entities [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total Unfunded Commitments	$ 34	$ 48
Redemption Frequency (Quarterly)	87.00%	89.00%
Redemption Frequency (Not Redeemable)	13.00%	11.00%
Hedge Funds/Funds of Hedge Funds/Other [Member] \| Consolidated Variable Interest Entities [Member] \| Fair Value Measured at NAV per share [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	$ 318	$ 385
Private Equity Funds [Member] \| Consolidated Variable Interest Entities [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total Unfunded Commitments	22	34
Private Equity Funds [Member] \| Consolidated Variable Interest Entities [Member] \| Fair Value Measured at NAV per share [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	266	181
Real Assets Funds [Member] \| Consolidated Variable Interest Entities [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total Unfunded Commitments	92	29
Real Assets Funds [Member] \| Consolidated Variable Interest Entities [Member] \| Fair Value Measured at NAV per share [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	$ 601	$ 372
Other Funds [Member] \| Minimum [Member] \| Consolidated Variable Interest Entities [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Redemption Notice Period, days	60 days	60 days
Other Funds [Member] \| Maximum [Member] \| Consolidated Variable Interest Entities [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Redemption Notice Period, days	90 days	90 days
Equity Method Investments [Member] \| Hedge Funds/Funds of Hedge Funds/Other [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total Unfunded Commitments	$ 174	$ 150
Redemption Frequency (Daily)	1.00%
Redemption Frequency (Monthly)	1.00%
Redemption Frequency (Quarterly)	13.00%	12.00%
Redemption Frequency (Not Redeemable)	86.00%	88.00%
Equity Method Investments [Member] \| Hedge Funds/Funds of Hedge Funds/Other [Member] \| Fair Value Measured at NAV per share [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	$ 423	$ 446
Equity Method Investments [Member] \| Hedge Funds/Funds of Hedge Funds/Other [Member] \| Minimum [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Redemption Notice Period, days	1 day	1 day
Equity Method Investments [Member] \| Hedge Funds/Funds of Hedge Funds/Other [Member] \| Maximum [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Redemption Notice Period, days	90 days	90 days
Equity Method Investments [Member] \| Private Equity Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total Unfunded Commitments	$ 214	$ 225
Equity Method Investments [Member] \| Private Equity Funds [Member] \| Fair Value Measured at NAV per share [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	453	510
Equity Method Investments [Member] \| Real Assets Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total Unfunded Commitments	$ 1,680	$ 1,870
Redemption Frequency (Quarterly)	4.00%	7.00%
Redemption Frequency (Not Redeemable)	96.00%	93.00%
Redemption Notice Period, days	60 days	60 days
Equity Method Investments [Member] \| Real Assets Funds [Member] \| Fair Value Measured at NAV per share [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	$ 849	$ 524
Equity Method Investments [Member] \| Investments Related To Deferred Cash Compensation Plans [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total Unfunded Commitments	0	0
Equity Method Investments [Member] \| Investments Related To Deferred Cash Compensation Plans [Member] \| Fair Value Measured at NAV per share [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	$ 455	$ 300
Equity Method Investments [Member] \| Investments Related To Deferred Cash Compensation Plans [Member] \| Minimum [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Redemption Notice Period, days	1 day	1 day
Equity Method Investments [Member] \| Investments Related To Deferred Cash Compensation Plans [Member] \| Maximum [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Redemption Notice Period, days	90 days	90 days
Other Investments [Member] \| Private Credit Fund [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total Unfunded Commitments	$ 0	$ 0
Redemption Notice Period, days	30 days	30 days
Other Investments [Member] \| Private Credit Fund [Member] \| Fair Value Measured at NAV per share [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	$ 148	$ 140

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Fair value measured recurring basis using net asset per share value redemption frequency not redeemable.

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Fair value of investment other than investment in equity security, investment in debt security and equity method investment. Includes, but is not limited to, investment in certain entities that calculate net asset value per share. Example includes, but is not limited to, investment in hedge fund, venture capital fund, private equity fund, and real estate partnership or fund.

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- Definition

Period required for notice to be delivered before investment, calculated using net asset value (NAV) per share, can be redeemed, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, investment calculated using unit, membership interest, other equity or ownership interest, and alternative investment.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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