Retirement Benefits and Trusteed Assets (Details 6) (Pension Plans, Defined Benefit [Member], USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Schedule of Defined Benefit Plans Fair Value Hierachy Level Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	$ 2,886	$ 2,913	$ 2,549
Fair Value, Inputs, Level 1 [Member]
Schedule of Defined Benefit Plans Fair Value Hierachy Level Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	1,469	1,402
Fair Value, Inputs, Level 2 [Member]
Schedule of Defined Benefit Plans Fair Value Hierachy Level Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	953	1,033
Fair Value, Inputs, Level 3 [Member]
Schedule of Defined Benefit Plans Fair Value Hierachy Level Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	464	478
Short-term investments [Member]
Schedule of Defined Benefit Plans Fair Value Hierachy Level Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	33	34
Short-term investments [Member] | Fair Value, Inputs, Level 1 [Member]
Schedule of Defined Benefit Plans Fair Value Hierachy Level Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Short-term investments [Member] | Fair Value, Inputs, Level 2 [Member]
Schedule of Defined Benefit Plans Fair Value Hierachy Level Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	33	34
Short-term investments [Member] | Fair Value, Inputs, Level 3 [Member]
Schedule of Defined Benefit Plans Fair Value Hierachy Level Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Us Large Cap Equity Securities [Member]
Schedule of Defined Benefit Plans Fair Value Hierachy Level Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	680	724
Us Large Cap Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Schedule of Defined Benefit Plans Fair Value Hierachy Level Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	640	686
Us Large Cap Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Schedule of Defined Benefit Plans Fair Value Hierachy Level Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	40	38
Us Large Cap Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Schedule of Defined Benefit Plans Fair Value Hierachy Level Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
US Small Cap and Mid Cap Equity Securities [Member]
Schedule of Defined Benefit Plans Fair Value Hierachy Level Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	164	189
US Small Cap and Mid Cap Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Schedule of Defined Benefit Plans Fair Value Hierachy Level Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	159	181
US Small Cap and Mid Cap Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Schedule of Defined Benefit Plans Fair Value Hierachy Level Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	5	8
US Small Cap and Mid Cap Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Schedule of Defined Benefit Plans Fair Value Hierachy Level Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Non US Equity Securities [Member]
Schedule of Defined Benefit Plans Fair Value Hierachy Level Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	506	507
Non US Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Schedule of Defined Benefit Plans Fair Value Hierachy Level Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	392	285
Non US Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Schedule of Defined Benefit Plans Fair Value Hierachy Level Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	114	222
Non US Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Schedule of Defined Benefit Plans Fair Value Hierachy Level Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Fixed income securities [Member]
Schedule of Defined Benefit Plans Fair Value Hierachy Level Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	791	719
Fixed income securities [Member] | Fair Value, Inputs, Level 1 [Member]
Schedule of Defined Benefit Plans Fair Value Hierachy Level Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	88	61
Fixed income securities [Member] | Fair Value, Inputs, Level 2 [Member]
Schedule of Defined Benefit Plans Fair Value Hierachy Level Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	703	658
Fixed income securities [Member] | Fair Value, Inputs, Level 3 [Member]
Schedule of Defined Benefit Plans Fair Value Hierachy Level Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Hedge Funds and Similar Investments [Member]
Schedule of Defined Benefit Plans Fair Value Hierachy Level Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	544	566
Hedge Funds and Similar Investments [Member] | Fair Value, Inputs, Level 1 [Member]
Schedule of Defined Benefit Plans Fair Value Hierachy Level Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	190	189
Hedge Funds and Similar Investments [Member] | Fair Value, Inputs, Level 2 [Member]
Schedule of Defined Benefit Plans Fair Value Hierachy Level Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	58	73
Hedge Funds and Similar Investments [Member] | Fair Value, Inputs, Level 3 [Member]
Schedule of Defined Benefit Plans Fair Value Hierachy Level Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	296	304
Private Equity and Other [Member]
Schedule of Defined Benefit Plans Fair Value Hierachy Level Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	168	174
Private Equity and Other [Member] | Fair Value, Inputs, Level 1 [Member]
Schedule of Defined Benefit Plans Fair Value Hierachy Level Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Private Equity and Other [Member] | Fair Value, Inputs, Level 2 [Member]
Schedule of Defined Benefit Plans Fair Value Hierachy Level Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Private Equity and Other [Member] | Fair Value, Inputs, Level 3 [Member]
Schedule of Defined Benefit Plans Fair Value Hierachy Level Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	$ 168	$ 174