Litigation, Investigations and Claims (Unaudited) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended			12 Months Ended
	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2012 United States Postal Service	Dec. 31, 2007 United States Postal Service	Sep. 30, 2012 United States Postal Service Claims	Jun. 30, 2012 United States Postal Service Claims	Apr. 13, 2012 United States Postal Service Claims
Loss Contingencies [Line Items]
Contract award				$ 875
Period certified claims were submitted	2 years
Loss contingency, number of claims					3	3	2
Gain contingency, unrecorded amount			179
Receivables, unpaid long-term contracts	2,973	2,964	63
Claims asserted, range of possible loss, maximum	$ 737						$ 341