Other Postretirement Benefits (Fair Value Of Plan Assets) (Details) (Other Postretirement Benefits [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009	Dec. 31, 2008
Schedule Of Other Postretirement Benefits [Line Items]
Total investments	$ 606		$ 597
Funds for retiree health benefits	336	[1]	359	[1]
Investments (including funds for retiree health benefits)	942		956
Pending activities	5	[2]	(14)	[2]
Total fair value of plan net assets	947		942		866	737
Fair Value, Inputs, Level 1 [Member]
Schedule Of Other Postretirement Benefits [Line Items]
Total investments	115		118
Funds for retiree health benefits	174	[1]	226	[1]
Investments (including funds for retiree health benefits)	289		344
Fair Value, Inputs, Level 2 [Member]
Schedule Of Other Postretirement Benefits [Line Items]
Total investments	491		290
Funds for retiree health benefits	134	[1]	103	[1]
Investments (including funds for retiree health benefits)	625		393
Fair Value, Inputs, Level 3 [Member]
Schedule Of Other Postretirement Benefits [Line Items]
Total investments			189
Funds for retiree health benefits	28	[1]	30	[1]
Investments (including funds for retiree health benefits)	28		219
Total fair value of plan net assets			189		181
U.S. Equity [Member]
Schedule Of Other Postretirement Benefits [Line Items]
Total investments	277	[3]	290	[3]
U.S. Equity [Member] | Fair Value, Inputs, Level 1 [Member]
Schedule Of Other Postretirement Benefits [Line Items]
Total investments	115	[3]	118	[3]
U.S. Equity [Member] | Fair Value, Inputs, Level 2 [Member]
Schedule Of Other Postretirement Benefits [Line Items]
Total investments	162	[3]	172	[3]
U.S. Equity [Member] | Fair Value, Inputs, Level 3 [Member]
Schedule Of Other Postretirement Benefits [Line Items]
Total investments				[3]
International Equity [Member]
Schedule Of Other Postretirement Benefits [Line Items]
Total investments	104	[4]	107	[4]
International Equity [Member] | Fair Value, Inputs, Level 1 [Member]
Schedule Of Other Postretirement Benefits [Line Items]
Total investments		[4]		[4]
International Equity [Member] | Fair Value, Inputs, Level 2 [Member]
Schedule Of Other Postretirement Benefits [Line Items]
Total investments	104	[4]	107	[4]
International Equity [Member] | Fair Value, Inputs, Level 3 [Member]
Schedule Of Other Postretirement Benefits [Line Items]
Total investments		[4]		[4]
Other Fixed Income [Member]
Schedule Of Other Postretirement Benefits [Line Items]
Total investments	207	[5]	189	[5]
Other Fixed Income [Member] | Fair Value, Inputs, Level 1 [Member]
Schedule Of Other Postretirement Benefits [Line Items]
Total investments		[5]		[5]
Other Fixed Income [Member] | Fair Value, Inputs, Level 2 [Member]
Schedule Of Other Postretirement Benefits [Line Items]
Total investments	207	[5]		[5]
Other Fixed Income [Member] | Fair Value, Inputs, Level 3 [Member]
Schedule Of Other Postretirement Benefits [Line Items]
Total investments		[5]	189	[5]
Total fair value of plan net assets			189		173
Cash And Cash Equivalents [Member]
Schedule Of Other Postretirement Benefits [Line Items]
Total investments	18	[6]	11	[6]
Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]
Schedule Of Other Postretirement Benefits [Line Items]
Total investments		[6]		[6]
Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member]
Schedule Of Other Postretirement Benefits [Line Items]
Total investments	18	[6]	11	[6]
Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member]
Schedule Of Other Postretirement Benefits [Line Items]
Total investments		[6]		[6]

[1] The Companies set aside funds for retiree health benefits through a separate account within the pension trust, as permitted under Section 401(h) of the Internal Revenue Code of 1986, as amended. In accordance with the Code, the plan's investments in the 401(h) account may not be used for, or diverted to, any purpose other than providing health benefits for retirees. The net assets held in the 401(h) account are calculated based on a pro-rata percentage allocation of the net assets in the pension plan. The related obligations for health benefits are not included in the pension plan's obligations and are included in the Companies' other postretirement benefit obligation. See Note E.

[2] Pending activities include security purchases and sales that have not settled, interest and dividends that have not been received, and reflects adjustments for available estimates at year end.

[3] U.S. Equity includes both actively- and passively-managed assets with investments in domestic equity index funds and commingled funds.

[4] International Equity includes commingled international equity funds.

[5] Other Fixed Income includes commingled funds, which are valued at Net Asset Value (NAV).

[6] Cash and Cash Equivalents include short term investments and money markets.