Litigation, Investigations and Claims (Unaudited) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended			12 Months Ended
	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2012 United States Postal Service	Dec. 31, 2007 United States Postal Service	Jun. 30, 2012 United States Postal Service Claims	Apr. 13, 2012 United States Postal Service Claims	Dec. 31, 2011 United States Postal Service Claims
Loss Contingencies [Line Items]
Transition period, pension benefit, employer-funded portion	5 years
Contract award				$ 875
Loss Contingency, Pending Claims, Number					3	2	3
Gain contingency, unrecorded amount			179
Receivables, unpaid long-term contracts	3,119	2,964	63
Claims asserted, range of possible loss	$ 732					$ 341