Derivative Instruments - Offsetting Assets and Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Derivative assets
Gross amount recognized	$ 4,571	$ 3,309
Financial instruments	(1,665)	(1,477)
Collateral (received)/pledged	(3,140)	(1,952)
Net amount	(234)	(120)
Off-balance sheet securities collateral	0	0
Net amount after securities collateral	(234)	(120)
Derivative liabilities
Gross amount recognized	(1,892)	(1,646)
Financial instruments	1,665	1,477
Collateral (received)/pledged	655	478
Net amount	428	309
Off-balance sheet securities collateral	0	0
Net amount after securities collateral	428	309
Derivatives designated as hedges
Derivative assets
Gross amount recognized	1,101	1,164
Derivative liabilities
Gross amount recognized	(1,219)	(1,159)
Foreign currency forwards | Derivatives designated as hedges
Derivative assets
Gross amount recognized	437	406
Derivative liabilities
Gross amount recognized	(40)	(52)
Foreign currency swaps | Derivatives designated as hedges
Derivative assets
Gross amount recognized	647	747
Derivative liabilities
Gross amount recognized	(167)	(154)
Cross Currency Interest Rate Contract | Derivatives designated as hedges
Derivative assets
Gross amount recognized	0	0
Derivative liabilities
Gross amount recognized	(809)	(803)
Interest rate swaps | Derivatives designated as hedges
Derivative assets
Gross amount recognized	14	9
Derivative liabilities
Gross amount recognized	(203)	(150)
Interest sensitive contract liabilities | Foreign currency swaps | Fair Value Hedging [Member] | Derivatives designated as hedges
Derivative [Line Items]
Derivative, Amount of Hedged Item	1,369	1,081
Hedged Asset, Fair Value Hedge, Cumulative Increase (Decrease)	90	88
Interest sensitive contract liabilities | Cross Currency Interest Rate Contract | Fair Value Hedging [Member] | Derivatives designated as hedges
Derivative [Line Items]
Derivative, Amount of Hedged Item	3,724	4,348
Hedged Asset, Fair Value Hedge, Cumulative Increase (Decrease)	647	632
Interest sensitive contract liabilities | Interest rate swaps | Fair Value Hedging [Member] | Derivatives designated as hedges
Derivative [Line Items]
Derivative, Amount of Hedged Item	6,711	6,577
Hedged Asset, Fair Value Hedge, Cumulative Increase (Decrease)	386	323
AFS securities | Foreign currency forwards | Fair Value Hedging [Member] | Derivatives designated as hedges
Derivative [Line Items]
Derivative, Amount of Hedged Item	5,372	5,259
Hedged Asset, Fair Value Hedge, Cumulative Increase (Decrease)	(245)	(217)
AFS securities | Foreign currency swaps | Fair Value Hedging [Member] | Derivatives designated as hedges
Derivative [Line Items]
Derivative, Amount of Hedged Item	5,448	4,797
Hedged Asset, Fair Value Hedge, Cumulative Increase (Decrease)	$ (452)	$ (398)