CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Millions	Total	Class A Common Stock Class A Common Stock		Additional Paid-in- Capital	Retained Earnings	Treasury Stock, at Cost	Accumulated Other Comprehensive Loss
Beginning balance at Dec. 31, 2016	$ 5,121	$ 5		$ 5,808	$ 6,265	$ (6,460)	$ (497)
Beginning balance (in shares) at Dec. 31, 2016		386,100,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,459				1,459
Other comprehensive income (loss)	480						480
Dividends ($1.29 per share)	(482)				(482)
Share-based compensation plans (in shares)		2,200,000
Share-based compensation plans	29			(38)	0	67
Purchase of treasury stock	(3,025)					(3,025)
Purchase of treasury stock (in shares)		(29,200,000)
Ending balance at Dec. 31, 2017	3,582	$ 5		5,770	7,242	(9,418)	(17)
Ending balance (in shares) at Dec. 31, 2017		359,100,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,907				1,907
Other comprehensive income (loss)	(370)						(370)
Dividends ($1.29 per share)	(543)				(543)
Share-based compensation plans (in shares)		1,500,000
Share-based compensation plans	86			44	0	42
Purchase of treasury stock	(2,809)					(2,809)
Purchase of treasury stock (in shares)		(21,500,000)
Ending balance at Dec. 31, 2018	2,225	$ 5		5,814	8,982	(12,185)	(391)
Ending balance (in shares) at Dec. 31, 2018		339,100,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,273
Other comprehensive income (loss)	30						30
Dividends ($1.29 per share)	(612)				(612)
Share-based compensation plans (in shares)		2,200,000
Share-based compensation plans	46			(14)	0	60
Purchase of treasury stock	(2,260)					(2,260)
Purchase of treasury stock (in shares)		(17,300,000)
Ending balance at Dec. 31, 2019	$ 703	$ 5		$ 5,800	$ 9,644	$ (14,385)	$ (361)
Ending balance (in shares) at Dec. 31, 2019	324,000,000	324,000,000.0	[1]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock, authorized (in shares)	800,000,000
Common stock, par value (in USD per share)	$ 0.01
Preferred stock, authorized (in shares)	10,000,000
Preferred stock, outstanding (in shares)	0

[1] Our restated certificate of incorporation authorizes 800 million shares of our common stock, with a par value of $.01 per share and 10 million shares of preferred stock, without par value. At year-end 2019, we had 324 million of these authorized shares of our common stock and no preferred stock outstanding.