Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 1,314	$ 730	$ 855
Other comprehensive income (loss):
Net change in unrealized gains (losses) on non-credit impaired available-for-sale securities	(53)	66	88
Retirement plan liability adjustments	(1)	(2)	7
Foreign currency translation adjustments	1	2	5
Other	11	0	0
Income tax effect:
Net change in unrealized gains (losses) on non-credit impaired available-for-sale securities	12	(15)	(20)
Retirement plan liability adjustments	1	0	(1)
Foreign currency translation adjustments	0	0	(2)
Other	(3)	0	0
Other comprehensive income (loss), net of tax, before reclassification adjustments	(32)	51	77
Net realized gains (losses) on available-for-sale securities, net of tax	(1)	(1)	1
Reclassification adjustments included in net income, net of tax	(1)	(1)	1
Other comprehensive income (loss), net of tax	(33)	50	78
Comprehensive income	$ 1,281	$ 780	$ 933