Employee Benefits Schedule of Fair Value, Assets (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plan Disclosure [Line Items]
Domestic	$ 163	$ 163
Debt securities—Domestic government	3	2
Equity securities:
Domestic	13	5
Domestic	9
International	1
International	4	2
Debt securities:
Domestic government and corporate credit	78	138
Domestic government and corporate credit	3
Corporate credit	76	28
Private equity funds	32	23
Alternative investments	30
Defined Benefit Plan, Fair Value of Plan Assets	487	473
Other Postretirement Benefit Plans assets:
Money market funds	7	7
Equity securities:
Domestic	13	5
Domestic	9
International	1
International	4	2
Debt securities—Domestic government	12
Other post retirement benefit plan assets total	27	16
Money market funds	3	15
International	105	106
Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Domestic	151	52
Debt securities—Domestic government	3	2
Equity securities:
Domestic	12	3
Domestic	7	16
International	1	2
International	2	1
Debt securities:
Domestic government and corporate credit	0	68
Domestic government and corporate credit	3	2
Corporate credit	76	0
Private equity funds	0	0
Alternative investments	0
Defined Benefit Plan, Fair Value of Plan Assets	281	173
Other Postretirement Benefit Plans assets:
Money market funds	0	0
Equity securities:
Domestic	12	3
Domestic	7	16
International	1	2
International	2	1
Debt securities—Domestic government	3	3
Other post retirement benefit plan assets total	17	6
Money market funds	0	0
International	54	53
Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Domestic	12	111
Debt securities—Domestic government	0	0
Equity securities:
Domestic	1	2
Domestic	2	0
International	0	1
International	2	1
Debt securities:
Domestic government and corporate credit	78	70
Domestic government and corporate credit	0	0
Corporate credit	0	0
Private equity funds	0	0
Alternative investments	0
Defined Benefit Plan, Fair Value of Plan Assets	144	249
Other Postretirement Benefit Plans assets:
Money market funds	7	7
Equity securities:
Domestic	1	2
Domestic	2	0
International	0	1
International	2	1
Debt securities—Domestic government	9	9
Other post retirement benefit plan assets total	10	10
Money market funds	3	15
International	51	53
Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Domestic	0	0
Debt securities—Domestic government	0	0
Equity securities:
Domestic	0	0
Domestic	0	0
International	0	0
International	0	0
Debt securities:
Domestic government and corporate credit	0	0
Domestic government and corporate credit	0	0
Corporate credit	0	28
Private equity funds	32	23
Alternative investments	30
Defined Benefit Plan, Fair Value of Plan Assets	62	51
Other Postretirement Benefit Plans assets:
Money market funds	0	0
Equity securities:
Domestic	0	0
Domestic	0	0
International	0	0
International	0	0
Debt securities—Domestic government	0	0
Other post retirement benefit plan assets total	0	0
Money market funds	0	0
International	$ 0	$ 0