Employee Benefits Schedule of Fair Value, Assets (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Pension Plan assets:
Money market funds	$ 6
Equity securities:
Domestic	188	185
International equity securities - defined benefit pension plan assets	171	185
Debt securities:
Domestic government and corporate credit	197	181
Corporate credit		14
Private equity funds	29	31
Defined Benefit Plan, Fair Value of Plan Assets	591	596
Other Postretirement Benefit Plans assets: [Abstract]
Money market funds	6	10
Domestic equity securities - Other postretirement benefit plan assets at fair value	11	10
International equity securities - other post retirement assets at fair value	10	9
Debt securities—Domestic government	5	3
Other post retirement benefit plan assets total	32	32
Fair Value, Inputs, Level 1 [Member]
Defined Benefit Pension Plan assets:
Money market funds	0
Equity securities:
Domestic	42	166
International equity securities - defined benefit pension plan assets	0	185
Debt securities:
Domestic government and corporate credit	0	0
Corporate credit		14
Private equity funds	0	0
Defined Benefit Plan, Fair Value of Plan Assets	42	365
Other Postretirement Benefit Plans assets: [Abstract]
Money market funds	0	0
Domestic equity securities - Other postretirement benefit plan assets at fair value	10	8
International equity securities - other post retirement assets at fair value	10	9
Debt securities—Domestic government	5	3
Other post retirement benefit plan assets total	25	20
Fair Value, Inputs, Level 2 [Member]
Defined Benefit Pension Plan assets:
Money market funds	6
Equity securities:
Domestic	146	19
International equity securities - defined benefit pension plan assets	171	0
Debt securities:
Domestic government and corporate credit	197	181
Corporate credit		0
Private equity funds	0	0
Defined Benefit Plan, Fair Value of Plan Assets	520	200
Other Postretirement Benefit Plans assets: [Abstract]
Money market funds	6	10
Domestic equity securities - Other postretirement benefit plan assets at fair value	1	2
International equity securities - other post retirement assets at fair value	0	0
Debt securities—Domestic government	0	0
Other post retirement benefit plan assets total	7	12
Fair Value, Inputs, Level 3 [Member]
Defined Benefit Pension Plan assets:
Money market funds	0
Equity securities:
Domestic	0	0
International equity securities - defined benefit pension plan assets	0	0
Debt securities:
Domestic government and corporate credit	0	0
Corporate credit		0
Private equity funds	29	31
Defined Benefit Plan, Fair Value of Plan Assets	29	31	32
Other Postretirement Benefit Plans assets: [Abstract]
Money market funds	0	0
Domestic equity securities - Other postretirement benefit plan assets at fair value	0	0
International equity securities - other post retirement assets at fair value	0	0
Debt securities—Domestic government	0	0
Other post retirement benefit plan assets total	$ 0	$ 0