Employee Benefit Plans (Details 1) (USD $) In Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Pension Benefits [Member]
Net Periodic Benefit Cost Amortized From Accumulated Other Comprehensive Income (Loss)
Amortization of net actuarial (gains) losses	$ 48	$ 49	$ 97	$ 98
Amortization of prior service costs (credit)	1	1	2	3
Subtotal	49	50	99	101
Deferred income tax expense (benefit)	(15)	(18)	(34)	(36)
Components of net periodic benefit costs amortized from accumulated other comprehensive income (loss), net of income tax	34	32	65	65
Other Postretirement Benefits [Member]
Net Periodic Benefit Cost Amortized From Accumulated Other Comprehensive Income (Loss)
Amortization of net actuarial (gains) losses	10	10	21	19
Amortization of prior service costs (credit)	(27)	(20)	(54)	(41)
Subtotal	(17)	(10)	(33)	(22)
Deferred income tax expense (benefit)	7	28	11	26
Components of net periodic benefit costs amortized from accumulated other comprehensive income (loss), net of income tax	$ (10)	$ 18	$ (22)	$ 4