Retirement Benefits and Trusteed Assets Retirement Benefits and Trusted Assets (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Pension Plans, Defined Benefit [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Service Cost	$ 19	$ 17	$ 38	$ 33
Defined Benefit Plan, Interest Cost	37	39	73	78
Defined Benefit Plan, Expected Return on Plan Assets	(47)	(42)	(93)	(83)
Defined Benefit Plan, Amortization of Net Gains (Losses)	36	30	72	60
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	0	0	0	0
Defined Benefit Plan Net Transition Liability			0	0
Defined Benefit Plan, Special Termination Benefits			0	2
Defined Benefit Plan, Net Periodic Benefit Cost	45	44	90	90
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Service Cost	9	14	21	27
Defined Benefit Plan, Interest Cost	16	23	34	46
Defined Benefit Plan, Expected Return on Plan Assets	(19)	(16)	(37)	(31)
Defined Benefit Plan, Amortization of Net Gains (Losses)	12	14	24	28
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	(28)	(4)	(45)	(8)
Defined Benefit Plan Net Transition Liability			0	1
Defined Benefit Plan, Special Termination Benefits			0	0
Defined Benefit Plan, Net Periodic Benefit Cost	$ (10)	$ 31	$ (3)	$ 63