Restructuring and Other Items (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2012	Mar. 31, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Restructuring Cost and Reserve [Line Items]
Restructuring, Settlement and Impairment Provisions	$ 149		$ 3	$ 330	$ 154
Facilities and Fleet [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring, Settlement and Impairment Provisions	122		0	171	71
Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring, Settlement and Impairment Provisions	66		3	237	83
Gain on Divestiture of Slot Swaps [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring, Settlement and Impairment Provisions	$ (39)	$ (39)	$ 0	$ (78)	$ 0