Redeemable Noncontrolling Interests and Total Equity (Cumulative Foreign Currency Translation Adjustments, Net of Tax) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011
Total Equity
Net investments in non-U.S. dollar functional currency subsidiaries subject to hedges	$ 13,811		$ 12,325
Cumulative foreign currency translation adjustments resulting from net investments in subsidiaries with a non-U.S. dollar functional currency	348		581
Cumulative foreign currency translation adjustments resulting from realized or unrealized losses on hedges, net of tax	(471)	[1]	(576)	[1]
Total cumulative foreign currency translation adjustments, net of tax	(123)		5
Gain, net of tax, related to net investment hedges reclassified from other comprehensive income into income	$ 77

[1] A gain of $77 million, net of tax, related to net investment hedges was reclassified from other comprehensive income into income during 2012. The amount primarily related to the reversal of amounts recorded in cumulative other comprehensive income due to the incorrect application of hedge accounting on certain derivative contracts (see Note 12 for further information).