Summary of Significant Accounting Policies (Details 3) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Accumulated Other Comprehensive Loss
Unamortized benefit plan costs, net of tax benefit of $1,972 in 2013 and $3,149 in 2012	$ (3,000)	$ (4,790)
Cumulative translation adjustment	18	4
Net unrealized loss on marketable securities and cash flow hedges, net of tax benefit of $1 in 2013 and $0 in 2012	(2)	(1)
Total accumulated other comprehensive loss	(2,984)	(4,787)
Unamortized benefit plan costs - Tax Benefit	(1,972)	(3,149)
Net unrealized gain on marketable securities and cash flow hedges, tax	1	0
Unamortized benefit plan, actuarial loss, net of tax	3,300	5,100
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, Net of Tax	$ 319	$ 204	$ 91