Fair Value Measurements - Information about Valuation Inputs for Fixed Income Securities Classified as Level 3 (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021	Dec. 31, 2020
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Inputs Yield Rate	9.30%		7.20%
Asset-backed Securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Coupon rate	5.98%		5.97%
Fair Value Inputs Maturity	13 years 11 months 19 days		14 years 1 month 20 days
Yield	11.00%		10.20%
Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability	$ 5,738	$ 6,194	$ 6,199	$ 6,376
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Earnings	(204)	(145)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss	(176)	49
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements	(80)	(86)
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss)	(204)	(145)
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	(176)	49
Fair Value, Inputs, Level 3 [Member] | Investments [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability	86	76	91	78
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Earnings	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss	(4)	(2)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements	(1)	0
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	(4)	(2)
Fair Value, Inputs, Level 3 [Member] | Other Assets [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability	0	1	$ 0	1
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Earnings	0	0
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss)	0	0
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	0	$ 0
Corporate Obligations [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Inputs Maturity		2 years 6 months	2 years 9 months
Derivative Financial Instruments, Liabilities [Member] | Fair Value, Inputs, Level 3 [Member] | Derivative Financial Instruments, Liabilities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability	52	$ 65	$ 70	84
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Earnings	(17)	(17)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements	(2)	(2)
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss)	(17)	(17)
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	0	0
Variable Interest Entity, Primary Beneficiary [Member] | Investment Contracts [Member] | Fair Value, Inputs, Level 3 [Member] | Corporate Obligations [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability	3,131	3,103	3,320	3,215
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Earnings	(93)	(138)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss	(96)	26
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss)	(93)	(138)
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	(96)	26
Variable Interest Entity, Primary Beneficiary [Member] | Loan Origination Commitments [Member] | Fair Value, Inputs, Level 3 [Member] | Loans Receivable [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability	2,469	2,948	$ 2,718	$ 2,998
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Earnings	(96)	9
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss	(76)	24
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements	(78)	(84)
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss)	(96)	9
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	$ (76)	$ 24