Equity (Details 4) (Stock Options [Member], USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Stock Options [Member]
Shares Under Option
Shares Under Option Outstanding at January 1, 2012	34,713,526
Granted Shares Under Option	6,247,050
Exercised Shares Under Option	(3,817,301)
Expired Shares Under Option	(1,017,994)
Forfeited Shares Under Option	(972,210)
Shares Under Option Outstanding at December 31, 2012	35,153,071	34,713,526
Shares Under Option Aggregate number of stock options expected to vest at December 31, 2012	34,684,396
Shares Under Option Exercisable at December 31, 2012	24,530,711
Weighted Average Exercise Price
Weighted Average Exercise Price Outstanding at January 1, 2012	$ 40.22
Granted Weighted Average Exercise Price	$ 37.91	$ 45.16	$ 35.06
Exercised Weighted Average Exercise Price	$ 28.44
Expired Weighted Average Exercise Price	$ 47.35
Forfeited Weighted Average Exercise Price	$ 40.23
Weighted Average Exercise Price Outstanding at December 31, 2012	$ 40.89	$ 40.22
Weighted Average Exercise Price Aggregate number of stock options expected to vest at December 31, 2012	$ 40.94
Weighted Average Exercise Price Exercisable at December 31, 2012	$ 41.36
Weighted Average Remaining Contractual Term
Weighted Average Remaining Contractual Term Outstanding	5 years 6 months 0 days	5 years 4 months 6 days
Weighted Average Remaining Contractual Term Aggregate number of stock options expected to vest at December 31, 2012	5 years 4 months 28 days
Weighted Average Remaining Contractual Term Exercisable at December 31, 2012	4 years 1 month 28 days
Aggregate Intrinsic Value
Aggregate Intrinsic Value Outstanding at January 1, 2012	$ 0
Aggregate Intrinsic Value Outstanding at December 31, 2012	51	0
Aggregate Intrinsic Value Aggregate number of stock options expected to vest at December 31, 2012	51
Aggregate Intrinsic Value Exercisable at December 31, 2012	$ 50