Retirement Benefits and Trusteed 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	$ 25	$ 20	$ 49	$ 41
Defined Benefit Plan, Interest Cost	47	51	95	102
Defined Benefit Plan, Expected Return on Plan Assets	(66)	(61)	(133)	(122)
Defined Benefit Plan, Amortization of Gains (Losses)	50	43	101	85
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	56	53	112	108
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	12	18	28	36
Defined Benefit Plan, Interest Cost	21	31	45	61
Defined Benefit Plan, Expected Return on Plan Assets	(27)	(23)	(54)	(46)
Defined Benefit Plan, Amortization of Gains (Losses)	15	20	32	39
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	(36)	(7)	(59)	(14)
Defined Benefit Plan Net Transition Liability			0	1
Defined Benefit Plan, Special Termination Benefits			0	0
Defined Benefit Plan, Net Periodic Benefit Cost	$ (15)	$ 39	$ (8)	$ 77