Consolidated Statements of Stockholders' Equity - USD ($) $ in Millions	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Retained Earnings Cumulative effect adjustments from changes in accounting guidance, net of tax	Retained Earnings Balance, beginning of year, as adjusted	Accumulated Other Comprehensive Income (Loss)	Treasury Stock
Total stockholder's equity at beginning of period at Dec. 31, 2018		$ 683	$ 2,192	$ 9,277		$ 9,277	$ (878)	$ (57)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation			11					10
Dividends to common stockholders ($2.27, $3.48, and $3.40 per share)				(929)
Net income	$ 1,000			1,000
Other comprehensive (loss) income	929						929
Purchase of treasury stock								(23)
Total stockholder's equity at end of period at Dec. 31, 2019	12,215	683	2,203	9,348	$ (5)	9,343	51	(70)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation			8					17
Dividends to common stockholders ($2.27, $3.48, and $3.40 per share)				(952)
Net income	690			690
Other comprehensive (loss) income	752						752
Purchase of treasury stock								(18)
Total stockholder's equity at end of period at Dec. 31, 2020	12,707	683	2,211	9,081		$ 9,081	803	(71)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation			4					17
Dividends to common stockholders ($2.27, $3.48, and $3.40 per share)				(620)
Net income	1,202			1,202
Other comprehensive (loss) income	(483)						(483)
Purchase of treasury stock								(18)
Total stockholder's equity at end of period at Dec. 31, 2021	$ 12,809	$ 683	$ 2,215	$ 9,663			$ 320	$ (72)