Retirement Benefits (Components Of Net Periodic Benefit Cost) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1	$ 104
Interest cost	163	191
Expected return on assets	(180)	(166)
Amortization of Prior service cost	7	4
Amortization of Unrecognized net (gain) loss	23	61
Net periodic benefit cost	14	194
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	15
Interest cost	13	38
Expected return on assets	(4)	(4)
Amortization of Prior service cost	(61)	(7)
Amortization of Unrecognized net (gain) loss	(2)	(2)
Net periodic benefit cost	$ (54)	$ 40