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
Unrealized gains reclassified to retained earnings for ASU 2016-01, after tax				$ 0
Beginning Balance at Dec. 31, 2018		$ 397	$ 1,281	7,625	$ 22	$ (1,492)	$ 7,625
Share-based awards		0	(13)			16
Share-based compensation			16
Other			2			1
Net Income (Loss)	$ 1,123			1,123
Dividends declared				(182)
Other comprehensive income	342				342
Shares acquired - share repurchase authorization						0
Shares acquired - share-based compensation plans						(7)
Ending Balance at Jun. 30, 2019	9,131	$ 397	1,286	8,566	364	(1,482)
Beginning Balance (in shares) at Dec. 31, 2018		162.8
Share-based awards (in shares)		0.5
Shares acquired - share repurchase authorization (in shares)		0.0
Ending Balance (in shares) at Jun. 30, 2019		163.3
Dividends declared per common share		$ 1.12
Increase to allowance through retained earnings for ASU 2016-13, after-tax				0
Beginning Balance at Mar. 31, 2019		$ 397	1,277	8,229	210	(1,483)	8,229
Share-based awards		0	1			3
Share-based compensation			7
Other			1			0
Net Income (Loss)	428			428
Dividends declared				(91)
Other comprehensive income	154				154
Shares acquired - share repurchase authorization						0
Shares acquired - share-based compensation plans						(2)
Ending Balance at Jun. 30, 2019	9,131	$ 397	1,286	8,566	364	(1,482)
Beginning Balance (in shares) at Mar. 31, 2019		163.2
Share-based awards (in shares)		0.1
Shares acquired - share repurchase authorization (in shares)		0.0
Ending Balance (in shares) at Jun. 30, 2019		163.3
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	448	(1,544)	9,257
Share-based awards		0	(16)			12
Share-based compensation			16
Other			3			1
Net Income (Loss)	(317)			(317)
Dividends declared				(193)
Other comprehensive income	149				149
Shares acquired - share repurchase authorization						(256)
Shares acquired - share-based compensation plans						(3)
Ending Balance at Jun. 30, 2020	9,258	$ 397	1,309	8,745	597	(1,790)
Beginning Balance (in shares) at Dec. 31, 2019		162.9
Share-based awards (in shares)		0.4
Shares acquired - share repurchase authorization (in shares)		(2.5)
Ending Balance (in shares) at Jun. 30, 2020		160.8
Dividends declared per common share		$ 1.20
Increase to allowance through retained earnings for ASU 2016-13, after-tax				0
Beginning Balance at Mar. 31, 2020		$ 397	1,300	7,932	204	(1,791)	$ 7,932
Share-based awards		0	0			1
Share-based compensation			7
Other			2			0
Net Income (Loss)	909			909
Dividends declared				(96)
Other comprehensive income	393				393
Shares acquired - share repurchase authorization						0
Shares acquired - share-based compensation plans						0
Ending Balance at Jun. 30, 2020	$ 9,258	$ 397	$ 1,309	$ 8,745	$ 597	$ (1,790)
Beginning Balance (in shares) at Mar. 31, 2020		160.8
Share-based awards (in shares)		0.0
Shares acquired - share repurchase authorization (in shares)		0.0
Ending Balance (in shares) at Jun. 30, 2020		160.8
Dividends declared per common share		$ 0.60