Income Taxes Summary of Gross Unrecognized Income Tax Benefits (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Gross Unrecognized Income Tax Benefits [Line Items]
Balance at January 1	$ 444	$ 236	$ 224
Increases and decreases as a result of positions taken during prior years
Transfers from valuation allowances	13	0	0
Other increases	7	1	3
Other decreases, including currency translation	(7)	0	(14)
Balances related to acquired businesses	2	177	2
Increases as a result of positions taken during the current year	35	36	31
Decreases relating to settlements with tax authorities	(6)	0	(2)
Decreases as a result of a lapse of the applicable statute of limitations	(9)	(6)	(8)
Balance at December 31	$ 479	$ 444	$ 236