Condensed Consolidated Statements of Shareholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Common equities	Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income	Treasury Stock	Previously Reported Retained Earnings	Previously Reported Accumulated Other Comprehensive Income
Unrealized gains reclassified to retained earnings for ASU 2016-01, after tax				$ 0
Beginning Balance at Dec. 31, 2018		$ 397	$ 1,281	7,625		$ (1,492)	$ 7,625	$ 22
Share-based awards		0	(14)			13
Share-based compensation			9
Other			1			1
Net Income (Loss)	$ 695			695
Dividends declared				(91)
Other comprehensive income (loss)	188				$ 188
Shares acquired - share repurchase authorization						0
Shares acquired - share-based compensation plans						(5)
Ending Balance at Mar. 31, 2019	8,630	$ 397	1,277	8,229	210	(1,483)
Beginning Balance (in shares) at Dec. 31, 2018		162.8
Share-based awards (in shares)		0.4
Shares acquired - share repurchase authorization (in shares)		0.0
Ending Balance (in shares) at Mar. 31, 2019		163.2
Dividends declared per common share		$ 0.56
Increase to allowance through retained earnings for ASU 2016-13, after-tax	2			(2)
Beginning Balance at Dec. 31, 2019	9,864	$ 397	1,306	9,255		(1,544)	$ 9,257	$ 448
Share-based awards		0	(16)			11
Share-based compensation			9
Other			1			1
Net Income (Loss)	(1,226)			(1,226)
Dividends declared				(97)
Other comprehensive income (loss)	(244)				(244)
Shares acquired - share repurchase authorization						(256)
Shares acquired - share-based compensation plans						(3)
Ending Balance at Mar. 31, 2020	$ 8,042	$ 397	$ 1,300	$ 7,932	$ 204	$ (1,791)
Beginning Balance (in shares) at Dec. 31, 2019	198.3	162.9
Share-based awards (in shares)		0.4
Shares acquired - share repurchase authorization (in shares)		(2.5)
Ending Balance (in shares) at Mar. 31, 2020	198.3	160.8
Dividends declared per common share		$ 0.60