CONSOLIDATED BALANCE SHEET (PARENTHETICALS) (USD $) In Millions, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Allowance for doubtful accounts (in dollars)	$ 22	$ 19
Accumulated depreciation, property, plant and equipment (in dollars)	$ 5,484	$ 4,787
Preferred Stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred Stock, shares authorized (in shares)	250,000,000	250,000,000
Preferred Stock, shares issued (in shares)	0	0
Preferred Stock, shares outstanding (in shares)	0	0
Class A Common Stock [Member]
Common Stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common Stock, shares authorized (in shares)	900,000,000	900,000,000
Common Stock, shares issued (in shares)	111,999,687	106,144,075
Common Stock, shares outstanding (in shares)	111,999,687	106,144,075
Class B Common Stock [Member]
Common Stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common Stock, shares authorized (in shares)	25,000,000	25,000,000
Common Stock, shares issued (in shares)	0	0
Common Stock, shares outstanding (in shares)	0	0