Benefit Plans (Estimated Amounts To Be Recognized From Accumulated Other Comprehensive Income Into Net Periodic Benefit Cost) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2011
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Amortization of net actuarial loss	$ 47
Amortization of prior service credit
Total estimated amounts to be recognized	47
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Amortization of net actuarial loss
Amortization of prior service credit	(25)
Total estimated amounts to be recognized	$ (25)

The amounts in accumulated other comprehensive income related to gains and losses that are not recognized immediately and are expected to be recognized as components of net periodic benefit cost over the next fiscal year that follows the most recent annual statement of financial position presented.

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The amounts in accumulated other comprehensive income related to prior service cost or credit expected to be recognized as components of net periodic benefit cost over the next fiscal year that follows the most recent annual statement of financial position presented.

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- Definition

The aggregate amount in accumulated other comprehensive income expected to be recognized as a component of net periodic benefit cost over the fiscal year that follows the most recent annual statement of financial position presented, including the net gain (loss), net prior service cost or credit, and net transition asset or obligation.

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