Derivatives - Derivative Balance Sheet Classification (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	$ 10,503	$ 11,224
Fair Value	34	(42)
Asset Derivatives	70	17
Liability Derivatives	(36)	(59)
Available-for-sale Securities [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	515	413
Fair Value	0	0
Asset Derivatives	0	0
Liability Derivatives	0	0
Other investments
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	1,184	1,452
Fair Value	32	7
Asset Derivatives	35	10
Liability Derivatives	(3)	(3)
Other liabilities
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	8,804	9,359
Fair Value	2	(49)
Asset Derivatives	35	7
Liability Derivatives	(33)	(56)
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	7,824	8,447
Fair Value	(18)	(48)
Asset Derivatives	15	6
Liability Derivatives	(33)	(54)
Interest rate swaps | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	2,155	2,340
Fair Value	(1)	0
Asset Derivatives	2	0
Liability Derivatives	(3)	0
Interest rate swaps | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	6,600	7,200
Foreign currency swaps | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	524	437
Fair Value	53	6
Asset Derivatives	53	11
Liability Derivatives	0	(5)
Total cash flow hedges
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	2,679	2,777
Fair Value	52	6
Asset Derivatives	55	11
Liability Derivatives	(3)	(5)
Interest rate swaps and futures | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	6,969	7,567
Fair Value	(19)	(46)
Asset Derivatives	10	3
Liability Derivatives	(29)	(49)
Foreign currency swaps and forwards | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	641	558
Fair Value	1	0
Asset Derivatives	1	0
Liability Derivatives	0	0
Credit derivatives that purchase credit protection | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	5	112
Fair Value	0	(2)
Asset Derivatives	0	0
Liability Derivatives	0	(2)
Credit derivatives in offsetting positions | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	209	210
Fair Value	0	0
Asset Derivatives	4	3
Liability Derivatives	$ (4)	$ (3)