Retirement Benefits (Components Of Net Periodic Benefit Cost) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 386	$ 366	$ 333
Interest cost	757	737	712
Expected return on assets	(657)	(593)	(566)
Amortization of prior service cost	13	13	13
Amortization of Settlement
Amortization of unrecognized net (gain) loss	154	154	145
Net periodic benefit cost	653	677	637
Defined contribution plans	179	168	168
Net periodic benefit cost	832	845	805
Retiree Medical And Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	61	60	59
Interest cost	174	165	179
Expected return on assets	(20)	(18)	(14)
Amortization of prior service cost	(28)	(19)	(8)
Amortization of unrecognized net (gain) loss	(9)	(10)	(14)
Net periodic benefit cost	$ 178	$ 178	$ 202