Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Accounts receivable, Allowance for Doubtful Accounts	$ 57	$ 56
Common stock, par value (in dollars per share)	$ 0.1	$ 0.1
Common stock, authorized (in shares)	1,000,000,000	1,000,000,000
Common stock, outstanding (in shares)	374,000,000	375,000,000