Retirement Benefits (Components Of Net Periodic Benefit Cost) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 104	$ 97	$ 208	$ 192
Interest cost	191	189	382	379
Expected return on assets	(166)	(165)	(332)	(328)
Amortization of Prior service cost	3	3	7	7
Amortization of Unrecognized net (gain) loss	63	39	124	76
Net periodic benefit cost	195	163	389	326
Retiree Medical And Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	15	15	30	30
Interest cost	38	44	76	88
Expected return on assets	(4)	(5)	(8)	(10)
Amortization of Prior service cost	(7)	(7)	(14)	(14)
Amortization of Unrecognized net (gain) loss	(2)	(2)	(4)	(4)
Net periodic benefit cost	$ 40	$ 45	$ 80	$ 90