Pension Benefits (Fair Value Of Plan Assets) (Details) (Pension Benefits [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009	Dec. 31, 2008
Defined Benefit Plan Disclosure [Line Items]
Total investments	$ 8,516		$ 8,235
Funds for retiree health benefits	(336)	[1]	(359)	[1]
Investments (excluding funds for retiree health benefits)	8,180		7,876
Pending activities	(380)	[2]	(155)	[2]
Total fair value of plan net assets	7,800		7,721		6,877	5,836
Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	4,423		5,187
Funds for retiree health benefits	(174)	[1]	(226)	[1]
Investments (excluding funds for retiree health benefits)	4,249		4,961
Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	3,385		2,368
Funds for retiree health benefits	(134)	[1]	(103)	[1]
Investments (excluding funds for retiree health benefits)	3,251		2,265
Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	708		680
Funds for retiree health benefits	(28)	[1]	(30)	[1]
Investments (excluding funds for retiree health benefits)	680		650
U.S. Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	2,506	[3]	3,935	[4]
Total fair value of plan net assets
U.S. Equity [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	2,506	[3]	3,935	[4]
International Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	2,541	[5]	1,483	[6]
Total fair value of plan net assets					1
International Equity [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	1,904	[5]	1,249	[6]
International Equity [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	637	[5]	234	[6]
U.S. Government Issues [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	1,618	[7]	1,300	[7]
U.S. Government Issues [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	1,618	[7]	1,300	[7]
Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	762	[8]	700	[9]
Total fair value of plan net assets	94		129		143
Corporate Bonds [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	668	[8]	571	[9]
Corporate Bonds [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	94	[8]	129	[9]
Structured Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	13	[10]	87	[11]
Total fair value of plan net assets	13		87		91
Structured Assets [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	13	[10]	87	[11]
Other Fixed Income [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	96	[12]	97	[13]
Total fair value of plan net assets	29		66		46
Other Fixed Income [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	67	[12]	31	[13]
Other Fixed Income [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	29	[12]	66	[13]
Swaps [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets					(3)
Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	572	[14]	398	[14]
Total fair value of plan net assets	572		398		344
Real Estate [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	572	[14]	398	[14]
Cash And Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	408	[15]	235	[16]
Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	13	[15]	3	[16]
Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	$ 395	[15]	$ 232	[16]

[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 F.

[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 actively-managed small-capitalization equities.

[4] U.S. Equity includes both actively- and passively-managed assets with investments in domestic equity index funds, actively-managed small-capitalization equities, rights and warrants.

[5] International Equity includes international equity index funds and actively-managed international equities.

[6] International Equity includes international equity index funds, actively-managed international equities, rights and warrants.

[7] U.S. Government Issues include agency and treasury securities.

[8] Corporate Bonds classified as Level 3 include 144A illiquid securities.

[9] Corporate Bonds held in institutional mutual funds which are measured at Net Asset Value (NAV) are classified as Level 3.

[10] Structured Assets are measured using broker quotes and investment manager proprietary models and include commercial-mortgage-backed securities and collateralized mortgage obligations.

[11] Structured Assets are measured using broker quotes and investment manager proprietary models and include commercial-mortgage-backed securities, collateralized mortgage obligations and asset-backed securities.

[12] Other Fixed Income includes municipal bonds, sovereign debt and regional governments.

[13] Other Fixed Income includes emerging market debt valued using broker quotes, municipal bonds, sovereign debt, regional governments and government agencies.

[14] Real Estate investments include real estate funds based on appraised values that are broadly diversified by geography and property type.

[15] Cash and Cash Equivalents include short term investments, money markets, foreign currency and cash collateral.

[16] Cash and Cash Equivalents include short term investments, money markets and foreign currency.