Stock Compensation Plans and Other Compensation Arrangements (Details 2) (Stock Option, USD $) In Millions, except Share data in Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Stock Option
Stock Option Activity (Table Amounts)
Shares under option - outstanding at January 1, 2012	11,744
Shares under option - granted	0
Shares under option - exercised	(5,404)
Shares under option - cancelled and forfeited	(69)
Shares under option - outstanding at December 31, 2012	6,271	11,744
Shares under option - vested and expected to vest in the future at December 31, 2012	6,257
Shares under option - exercisable at December 31, 2012	4,874
Stock Options, Weighted Average Exercise Price (Table Amounts)
Weighted-average exercise price - outstanding at January 1, 2012	$ 53
Weighted-average exercise price - granted	$ 0
Weighted-average exercise price - exercised	$ 47
Weighted-average exercise price - cancelled and forfeited	$ 61
Weighted-average exercise price - outstanding at December 31, 2012	$ 58	$ 53
Weighted-average exercise price - vested and expected to vest in the future at December 31, 2012	$ 58
Weighted-average exercise price - exercisable at December 31, 2012	$ 58
Weighted-average remaining contractual term - outstanding	2 years 10 months 28 days	3 years 4 months 26 days
Weighted-average remaining contractual term - vested and expected to vest in the future at December 31, 2012 (Years)	2 years 10 months 28 days
Weighted-average remaining contractual term - exercisable at December 31, 2012 (Years)	2 years 6 months 2 days
Aggregate intrinsic value - outstanding	$ 66	$ 93
Aggregate intrinsic value - vested and expected to vest in the future at December 31, 2012	66
Aggregate intrinsic value - exercisable at December 31, 2012	$ 53