Employee Benefit Plans (Details) (USD $) In Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Employee Benefit Plans (Textual)
Contributions to pension plans			$ 207	$ 54
Pension Plans, Defined Benefit [Member]
Components of net periodic benefit cost:
Service cost	28	22	73	65
Interest cost	21	21	64	62
Expected return on plan assets	(28)	(28)	(84)	(84)
Amortization of:
Prior service cost (credit)	1	1	2	2
Net loss	3	0	9	1
Net periodic benefit cost	25	16	64	46
Other Postretirement Benefit Plans, Defined Benefit [Member]
Components of net periodic benefit cost:
Service cost	4	3	9	8
Interest cost	5	6	16	19
Expected return on plan assets	0	0	0	0
Amortization of:
Prior service cost (credit)	(6)	(5)	(17)	(15)
Net loss	0	1	1	3
Net periodic benefit cost	$ 3	$ 5	$ 9	$ 15