Employee Benefit Plans (Details 1) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Defined Benefit Plan Disclosure [Line Items]
Defined Contribution Plan Contribution Match Percent	50.00%		50.00%
Pension Benefits [Member]
Component of periodic benefit cost
Service cost	$ 20	$ 24	$ 70	$ 76
Interest cost	64	64	188	194
Expected return on plan assets	(78)	(74)	(234)	(223)
Amortization of prior service credit	(2)	(2)	(7)	(7)
Amortization of actuarial loss	52	40	171	119
Curtailment gain due to plan freeze	0	0	(11)	0
Net periodic benefit cost	56	52	177	159
Other Postretirement Benefits [Member]
Component of periodic benefit cost
Service cost	0	2	2	4
Interest cost	3	5	11	15
Expected return on plan assets	(4)	(3)	(11)	(10)
Amortization of prior service credit	(2)	(1)	(3)	(1)
Amortization of actuarial loss	0	0	0	0
Curtailment gain due to plan freeze	0	0	0	0
Net periodic benefit cost	$ (3)	$ 3	$ (1)	$ 8