Employee Benefit Plans (Details 1) (USD $) In Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Net Periodic Benefit Cost Amortized From Accumulated Other Comprehensive Income (Loss)
Components of net periodic benefit costs amortized from accumulated other comprehensive income (loss), net of income tax			$ 65	$ 94
Pension Benefits [Member]
Net Periodic Benefit Cost Amortized From Accumulated Other Comprehensive Income (Loss)
Amortization of net actuarial (gains) losses	49	49	146	147
Amortization of prior service costs (credit)	1	2	3	5
Subtotal	50	51	149	152
Deferred income tax expense (benefit)	(18)	(17)	(52)	(53)
Components of net periodic benefit costs amortized from accumulated other comprehensive income (loss), net of income tax	32	34	97	99
Other Postretirement Benefits [Member]
Net Periodic Benefit Cost Amortized From Accumulated Other Comprehensive Income (Loss)
Amortization of net actuarial (gains) losses	11	9	32	28
Amortization of prior service costs (credit)	(27)	(21)	(81)	(62)
Subtotal	(16)	(12)	(49)	(34)
Deferred income tax expense (benefit)	6	3	17	29
Components of net periodic benefit costs amortized from accumulated other comprehensive income (loss), net of income tax	$ (10)	$ (9)	$ (32)	$ (5)