Consolidated Statements of Equity - USD ($) shares in Millions, $ in Millions	Total	Senior Preferred Stock	Preferred Stock, at Redemption Value	Common Stock, at Par Value	Additional Paid-In Capital	Retained Earnings (Accumulated Deficit)	AOCI, Net of Tax	Treasury Stock, at Cost
Beginning balance at Dec. 31, 2018	$ 4,477	$ 72,648	$ 14,109	$ 0	$ 0	$ (78,260)	$ (135)	$ (3,885)
Beginning balance, Shares at Dec. 31, 2018		1	464	650
Comprehensive income:
Net income (loss)	1,407					1,407
Other comprehensive income, net of taxes	258						258
Comprehensive income (loss)	1,665					1,407	258
Senior Preferred Stock Dividends Paid	(1,477)					(1,477)
Ending balance at Mar. 31, 2019	4,665	$ 72,648	$ 14,109	$ 0	0	(78,330)	123	(3,885)
Ending balance, Shares at Mar. 31, 2019		1	464	650
Comprehensive income:
Retained Earnings (Accumulated Deficit)	(74,188)
Beginning balance at Dec. 31, 2019	9,122	$ 72,648	$ 14,109	$ 0	0	(74,188)	438	(3,885)
Beginning balance, Shares at Dec. 31, 2019		1	464	650
Comprehensive income:
Net income (loss)	173					173
Other comprehensive income, net of taxes	449						449
Comprehensive income (loss)	622					173	449
Cumulative effect of change in accounting principle | Accounting Standards Update 2016-13	(240)
Ending balance at Mar. 31, 2020	9,504	$ 72,648	$ 14,109	$ 0	$ 0	$ (74,255)	$ 887	$ (3,885)
Ending balance, Shares at Mar. 31, 2020		1	464	650
Comprehensive income:
Retained Earnings (Accumulated Deficit)	$ (74,255)