CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Accounts receivable, allowances	$ 43	$ 43
Preferred stock, par value (in usd per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in usd per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	1,000,000,000.0	1,000,000,000
Common stock, shares issued (in shares)	342,902,272	342,902,272
Treasury stock, shares (in shares)	155,215,143	151,598,695
Series Common Stock
Common stock, par value (in usd per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	10,000,000	10,000,000
Common stock, shares issued (in shares)	0	0
Common stock, shares outstanding (in shares)	0	0