CONSOLIDATED STATEMENT OF CHANGES IN EQUITY (UNAUDITED) - USD ($) $ in Millions	Total	Preferred stock	Common stock	Additional paid-in capital	Retained earnings	Accumulated other comprehensive loss
Balance at beginning of period at Dec. 31, 2021		$ 1,265
Balance at beginning of period, common equity at Dec. 31, 2021			$ 0	$ 14,742	$ 1,212	$ (179)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Employee benefit plans				(5)
Net income	$ 291				291
Cash dividends declared on preferred stock					(38)
Cash dividends declared on common stock					0
Other comprehensive income (loss), net of tax	(1,751)					(1,751)
Balance at end of period, common equity at Jun. 30, 2022	14,272		0	14,737	1,465	(1,930)
Balance at end of period at Jun. 30, 2022	15,537	1,265
Balance at beginning of period at Mar. 31, 2022		1,265
Balance at beginning of period, common equity at Mar. 31, 2022			0	14,740	1,413	(1,345)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Employee benefit plans				(3)
Net income	90				90
Cash dividends declared on preferred stock					(38)
Cash dividends declared on common stock					0
Other comprehensive income (loss), net of tax	(585)					(585)
Balance at end of period, common equity at Jun. 30, 2022	14,272		0	14,737	1,465	(1,930)
Balance at end of period at Jun. 30, 2022	15,537	1,265
Balance at beginning of period at Dec. 31, 2022	12,113	265
Balance at beginning of period, common equity at Dec. 31, 2022	11,848		0	12,740	1,683	(2,575)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Employee benefit plans				(5)
Net income	368				368
Cash dividends declared on preferred stock					(8)
Cash dividends declared on common stock					(1,000)
Other comprehensive income (loss), net of tax	189					189
Balance at end of period, common equity at Jun. 30, 2023	11,392		0	12,735	1,043	(2,386)
Balance at end of period at Jun. 30, 2023	11,657	265
Balance at beginning of period at Mar. 31, 2023		265
Balance at beginning of period, common equity at Mar. 31, 2023			0	12,736	1,900	(2,210)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Employee benefit plans				(1)
Net income	151				151
Cash dividends declared on preferred stock					(8)
Cash dividends declared on common stock					(1,000)
Other comprehensive income (loss), net of tax	(176)					(176)
Balance at end of period, common equity at Jun. 30, 2023	11,392		$ 0	$ 12,735	$ 1,043	$ (2,386)
Balance at end of period at Jun. 30, 2023	$ 11,657	$ 265