CONSOLIDATED STATEMENT OF CHANGES IN EQUITY - USD ($) $ in Millions	Total	Preferred stock	Common stock	Additional paid-in capital	Retained earnings	Accumulated other comprehensive income (loss)	Cumulative Effect, Period of Adoption, Adjustment Retained earnings	Cumulative Effect, Period of Adoption, Adjustment Student Loans Retained earnings	Cumulative Effect, Period of Adoption, Reclassification Retained earnings	Cumulative Effect, Period of Adoption, Reclassification Accumulated other comprehensive income (loss)	Cumulative Effect, Period of Adoption, Adjusted Balance Retained earnings	Cumulative Effect, Period of Adoption, Adjusted Balance Accumulated other comprehensive income (loss)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Number of shares at beginning and end of period		1,265	714
Balance at beginning of period at Dec. 31, 2018		$ 1,265
Balance at beginning of period, common equity at Dec. 31, 2018			$ 0	$ 18,136	$ 1,471	$ (366)	$ 27				$ 1,498	$ (366)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Return of capital to parent				(2,400)
Employee benefit plans				0
Net income (loss)	$ 113				113
Cash dividends declared on preferred stock					(77)
Other comprehensive income (loss), net of tax	87					87
Balance at end of period, common equity at Dec. 31, 2019	16,991		$ 0	15,736	1,534	(279)	$ 84	$ 2	$ (2)	$ 2	1,618	(277)
Balance at end of period at Dec. 31, 2019	18,256	$ 1,265
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Number of shares at beginning and end of period		1,265	714
Return of capital to parent				0
Employee benefit plans				10
Net income (loss)	(940)				(940)
Cash dividends declared on preferred stock					(77)
Other comprehensive income (loss), net of tax	956					956
Balance at end of period, common equity at Dec. 31, 2020	17,026		$ 0	15,746	601	679					$ 601	$ 679
Balance at end of period at Dec. 31, 2020	18,291	$ 1,265
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Number of shares at beginning and end of period		1,265	714
Return of capital to parent				(1,000)
Employee benefit plans				(4)
Net income (loss)	688				688
Cash dividends declared on preferred stock					(77)
Other comprehensive income (loss), net of tax	(858)					(858)
Balance at end of period, common equity at Dec. 31, 2021	15,775		$ 0	$ 14,742	$ 1,212	$ (179)
Balance at end of period at Dec. 31, 2021	$ 17,040	$ 1,265
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Number of shares at beginning and end of period		1,265	714