Other Postretirement Benefits (Reconciliation Of Net Balances) (Details) (Other Postretirement Benefits [Member], USD $) In Millions, unless otherwise specified					12 Months Ended		12 Months Ended		12 Months Ended		12 Months Ended		12 Months Ended
Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008	Dec. 31, 2011 Fair Value, Inputs, Level 3 [Member]	Dec. 31, 2010 Fair Value, Inputs, Level 3 [Member]	Dec. 31, 2009 Fair Value, Inputs, Level 3 [Member]	Dec. 31, 2011 Fair Value, Inputs, Level 3 [Member] Other Fixed Income [Member]	Dec. 31, 2010 Fair Value, Inputs, Level 3 [Member] Other Fixed Income [Member]	Dec. 31, 2009 Fair Value, Inputs, Level 3 [Member] Other Fixed Income [Member]	Dec. 31, 2010 Fair Value, Inputs, Level 3 [Member] Insurance Contracts [Member]	Dec. 31, 2009 Fair Value, Inputs, Level 3 [Member] Insurance Contracts [Member]	Dec. 31, 2011 Fair Value, Inputs, Level 3 [Member] Funds For Retiree Health Benefits [Member]	Dec. 31, 2010 Fair Value, Inputs, Level 3 [Member] Funds For Retiree Health Benefits [Member]	Dec. 31, 2009 Fair Value, Inputs, Level 3 [Member] Funds For Retiree Health Benefits [Member]	Dec. 31, 2011 Fair Value, Inputs, Level 3 [Member] Investments (Including Funds For Retiree Health Benefits) [Member]	Dec. 31, 2010 Fair Value, Inputs, Level 3 [Member] Investments (Including Funds For Retiree Health Benefits) [Member]	Dec. 31, 2009 Fair Value, Inputs, Level 3 [Member] Investments (Including Funds For Retiree Health Benefits) [Member]
Schedule Of Other Postretirement Benefits [Line Items]
Beginning Balance as of January 1	$ 947	$ 942	$ 866	$ 737		$ 189	$ 181		$ 189	$ 173		$ 8	$ 28	$ 30	$ 28	$ 28	$ 219	$ 209
Assets Still Held at Reporting Date - Unrealized Gains/(Losses)						11			11				(3)	3		(3)	14
Assets Sold During the Period - Realized Gains/(Losses)									1		(1)		(1)	2		(1)	2
Purchases Sales and Settlements						(3)			4		(7)		2	(3)		2	(6)
Transfers Out of Level 3					(189)			(189)								(189)
Ending Balance as of December 31	$ 947	$ 942	$ 866	$ 737		$ 189	$ 181		$ 189	$ 173		$ 8	$ 28	$ 30	$ 28	$ 28	$ 219	$ 209

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Actual return on plan assets, separately identifying the amount related to assets sold during the period.

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Actual return on plan assets, separately identifying the amount related to assets still held at the reporting date.

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Assets, usually stocks, bonds, and other investments, that have been segregated and restricted (usually in a trust) to provide benefits, at their fair value as of the measurement date. Plan assets include amounts contributed by the employer (and by employees for a contributory plan) and amounts earned from investing the contributions, less benefits paid. If a plan has liabilities other than for benefits, those non-benefit obligations may be considered as reductions of plan assets.

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Purchases, sales, and settlements of plan assets that occurred during the period.

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Represents a decrease to the amount of certain investments for which net asset value per share is calculated (including by unit, membership interest, or other equity (ownership interest) unit measure) (alternative investments) due to transfers out of the Level 3 category for purposes of measuring fair value. Such transfers may, for example, be due to changes in the observability of significant measurement inputs.

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