Employee Benefit Plans (Details) (USD $) In Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Pension Benefits [Member]
Components of net periodic benefit costs
Service costs	$ 63	$ 44	$ 126	$ 88
Interest costs	105	100	210	199
Expected return on plan assets	(113)	(112)	(227)	(224)
Settlement and curtailment costs	0	7	0	7
Amortization of net actuarial (gains) losses	48	49	97	98
Amortization of prior service costs (credit)	1	1	2	3
Net periodic benefit costs	104	89	208	171
Other Postretirement Benefits [Member]
Components of net periodic benefit costs
Service costs	4	5	9	9
Interest costs	27	28	54	56
Expected return on plan assets	(19)	(21)	(39)	(40)
Settlement and curtailment costs	0	0	0	0
Amortization of net actuarial (gains) losses	10	10	21	19
Amortization of prior service costs (credit)	(27)	(20)	(54)	(41)
Net periodic benefit costs	$ (5)	$ 2	$ (9)	$ 3