Derivatives and Hedging Activities (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Derivatives, Fair Value [Line Items]
Total fair value of derivative assets	$ 581	$ 629
Total fair value of derivative liabilities	194	702
Derivative asset and derivative liability netting, assets	(97)	(98)
Derivative asset and derivative liability netting, liabilities	(97)	(98)
Other Assets
Derivatives, Fair Value [Line Items]
Total derivatives assets, net	132	31
Cash collateral netting, assets	(352)	(500)
Other Assets | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total fair value of derivative assets	428	524
Other Assets | Interest Rate Contract | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total derivatives assets, net	352	500
Other Assets | Foreign Exchange Contract | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total derivatives assets, net	76	24
Other Assets | Foreign Exchange Contract | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total fair value of derivative assets	153	105
Other Liabilities
Derivatives, Fair Value [Line Items]
Total derivative liabilities, net	97	588
Cash collateral netting, liabilities	0	(16)
Other Liabilities | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total fair value of derivative liabilities	129	474
Other Liabilities | Interest Rate Contract | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total derivative liabilities, net	0	0
Other Liabilities | Foreign Exchange Contract | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total derivative liabilities, net	129	474
Other Liabilities | Foreign Exchange Contract | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total fair value of derivative liabilities	$ 65	$ 228