Retirement Benefits (Components Of Net Periodic Benefit Cost) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 104	$ 97	$ 312	$ 289
Interest cost	191	189	573	568
Expected return on assets	(166)	(165)	(498)	(493)
Amortization of Prior service cost	3	3	10	10
Amortization of Unrecognized net (gain) loss	63	39	187	115
Net periodic benefit cost	195	163	584	489
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	15	15	45	45
Interest cost	38	44	114	132
Expected return on assets	(4)	(5)	(12)	(15)
Amortization of Prior service cost	(7)	(7)	(21)	(21)
Amortization of Unrecognized net (gain) loss	(2)	(2)	(6)	(6)
Net periodic benefit cost	$ 40	$ 45	$ 120	$ 135