Derivative and Hedging Activities - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Derivative [Line Items]
Interest income	$ 318	$ 282	$ 967	$ 792
Gain (losses) on interest rate derivatives designated as cash flow hedge			18
Interest rate cash flow hedge gain (loss) to be reclassified during next 12 months, net	26		26
Interest Rate Swap | Cash Flow Hedging
Derivative [Line Items]
Derivative, notional amount	2,250		2,250		$ 2,250
Designated as Hedging Instrument
Derivative [Line Items]
Derivative, notional amount	2,000		2,000		$ 2,000
Interest income	12	$ 11	37	$ 23
Designated as Hedging Instrument | Interest Rate Swap
Derivative [Line Items]
Derivative, notional amount	2,000		2,000
LCH | Designated as Hedging Instrument | Interest Rate Swap
Derivative [Line Items]
Derivative, notional amount	$ 4,300		$ 4,300