CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Millions	Total	Common Stock Member	Additional Paid In Capital Member	Retained Earnings Member	Treasury Stock Member	Accumulated Other Comprehensive Income Member
Total stockholders equity at Dec. 31, 2016	$ 7,093	$ 1	$ 1,849	$ 5,199	$ (1,095)	$ 1,139
Increase (Decrease) in Stockholders' Equity [Roll Forward]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification | Accounting Standards Update 2018-02 [Member]	18			(139)		157
Net Income (Loss) Attributable to Parent	1,822			1,822
Other Comprehensive Income (Loss), Net of Tax	768					768
Dividends to stockholders, $2.60 per share	(117)			(117)
Purchase of treasury stock	(43)				43
Reissuance of treasury stock	(29)		(22)	(29)	(36)
Total stockholders equity at Dec. 31, 2017	9,570	1	1,871	6,736	(1,102)	2,064
Increase (Decrease) in Stockholders' Equity [Roll Forward]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification | Accounting Standards Update 2018-02 [Member]	(3)			1		(4)
Net Income (Loss) Attributable to Parent	716			716
Other Comprehensive Income (Loss), Net of Tax	(1,424)					(1,424)
Dividends to stockholders, $2.60 per share	(140)			(140)
Purchase of treasury stock	(300)				300
Reissuance of treasury stock	(31)		(28)	(28)	(31)
Total stockholders equity at Dec. 31, 2018	8,450	1	1,899	7,285	(1,371)	636
Increase (Decrease) in Stockholders' Equity [Roll Forward]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification | Accounting Standards Update 2018-02 [Member]	0			0
Net Income (Loss) Attributable to Parent	870			870
Other Comprehensive Income (Loss), Net of Tax	2,501					2,501
Dividends to stockholders, $2.60 per share	(163)			(163)
Purchase of treasury stock	(101)				101
Reissuance of treasury stock	(44)		(38)	(40)	(46)
Total stockholders equity at Dec. 31, 2019	$ 11,601	$ 1	$ 1,937	$ 7,952	$ (1,426)	$ 3,137