Accumulated Other Comprehensive Income (Loss) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated Other Comprehensive Income (Loss), Pension and Other Benefit Liabilities, Net of Tax	$ (5,349)	$ (8,314)	$ (6,292)	$ (3,271)
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Derivative Contracts Net of Tax	219	(263)	(474)	(307)
Accumulated Other Comprehensive Loss	(5,130)	(8,577)	(6,766)	(3,578)
Other Comprehensive Income (Loss), Pension and Other Benefit Liabilities, Net Unamortized Gain (Loss) Arising During Period, Net of Tax	2,741	(2,171)	(3,062)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	296	196	5
Accumulated Other Comprehensive Income Loss Changes In Fair Value Net of Tax	3,037	(1,975)	(3,057)
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Benefit Liabilities, Net of Tax	224	149	41
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax	186	15	(172)
Accumulated Other Comprehensive Income (Loss) Reclassification To Earnings Net of Tax	$ 410	$ 164	$ (131)