Pension and Other Postretirment Benefits (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Pension And Other Postretirement Footnote Text Details [Abstract]
Decrease to postretirement benefits liability adjustment pre-tax			$ 54
Decrease to postretirement benefits liability adjustement after-tax			36
Total domestic pension plan contributions			112
Required domestic pension plan contributions			44
Voluntary Domestic Pension Plan Contributions			68
Expected additional contributions to Company's pension plans for the remainder of the year	138		138
Defined Benefit Pension Member
Pension And Other Postretirement Benefits Table [Line Items]
Service cost	0	0	1	1
Interest cost	50	57	99	114
Expected long-term return on plan assets	(67)	(68)	(134)	(133)
Amortization of net loss from past experience	15	10	30	19
Amortization of prior service cost	0	0	0	0
Settlement loss (gain)	0	0	6	0
Net pension cost	(2)	(1)	2	1
Other Postretirement Benefit Plans Defined Benefit Member
Pension And Other Postretirement Benefits Table [Line Items]
Service cost	1	1	1	1
Interest cost	4	5	8	10
Expected long-term return on plan assets	0	(1)	0	(1)
Amortization of net loss from past experience	0	0	0	0
Amortization of prior service cost	(3)	(4)	(6)	(8)
Settlement loss (gain)	0	0	0	0
Net pension cost	$ 2	$ 1	$ 3	$ 2