Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Accumulated other comprehensive income (loss)
Beginning balance	$ 2,718	$ 2,201
Other comprehensive income, net of tax	(37)	7
Ending balance	2,733	2,358
Investment Securities
Accumulated other comprehensive income (loss)
Beginning balance	15	52
Unrealized gain (loss)	(77)	(20)
Less: Tax provision (benefit)	(19)	(5)
Net unrealized gain (loss)	(58)	(15)
Other comprehensive income, net of tax	(58)	(15)
Ending balance	(43)	37
Cash Flow Hedges
Accumulated other comprehensive income (loss)
Beginning balance	20	(5)
Unrealized gain (loss)	29	26
Less: Tax provision (benefit)	8	5
Net unrealized gain (loss)	21	21
Reclassifications out of AOCI	0	1
Other comprehensive income, net of tax	21	22
Ending balance	$ 41	$ 17