CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012
Statement of Financial Position [Abstract]
Receivables, allowance for doubtful accounts (in dollars)	$ 67	$ 66	$ 70	$ 69	$ 62	$ 67	$ 56	$ 58	$ 53
Preferred Stock, par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01	$ 0.01	$ 0.01	$ 0.01	$ 0.01	$ 0.01	$ 0.01
Preferred Stock, shares authorized	200,000,000	200,000,000	200,000,000	200,000,000	200,000,000	200,000,000	200,000,000	200,000,000	200,000,000
Preferred Stock, shares issued	0	0	0	0	0	0	0	0	0
Preferred Stock, shares outstanding	0	0	0	0	0	0	0	0	0
Common Stock, par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01	$ 0.01	$ 0.01	$ 0.01	$ 0.01	$ 0.01	$ 0.01
Common Stock, shares authorized	2,000,000,000	2,000,000,000	2,000,000,000	2,000,000,000	2,000,000,000	2,000,000,000	2,000,000,000	2,000,000,000	2,000,000,000
Common Stock, shares issued	463,000,000	463,000,000	463,000,000	452,000,000	450,000,000	449,000,000	425,000,000	423,000,000	422,000,000
Common Stock, shares outstanding	459,000,000	459,000,000	459,000,000	448,000,000	446,000,000	421,000,000	401,000,000	400,000,000	422,000,000
Treasury stock, shares	4,000,000	4,000,000	4,000,000	4,000,000	4,000,000	0	23,000,000	23,000,000	0