Employee Benefits Schedule of Fair Value, Assets (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Pension Plan assets:
Money market funds	$ 5	$ 6
Equity securities:
Domestic	176	188
International equity securities - defined benefit pension plan assets	170	171
Debt securities:
Domestic government and corporate credit	177	197
Private equity funds	22	29
Defined Benefit Plan, Fair Value of Plan Assets	550	591
Other Postretirement Benefit Plans assets: [Abstract]
Money market funds	7	6
Domestic equity securities - Other postretirement benefit plan assets at fair value	10	11
International equity securities - other post retirement assets at fair value	8	10
Debt securities—Domestic government	5	5
Other post retirement benefit plan assets total	30	32
Fair Value, Inputs, Level 1 [Member]
Defined Benefit Pension Plan assets:
Money market funds	0	0
Equity securities:
Domestic	44	42
International equity securities - defined benefit pension plan assets	0	0
Debt securities:
Domestic government and corporate credit	0	0
Private equity funds	0	0
Defined Benefit Plan, Fair Value of Plan Assets	44	42
Other Postretirement Benefit Plans assets: [Abstract]
Money market funds	0	0
Domestic equity securities - Other postretirement benefit plan assets at fair value	0	10
International equity securities - other post retirement assets at fair value	8	10
Debt securities—Domestic government	0	5
Other post retirement benefit plan assets total	8	25
Fair Value, Inputs, Level 2 [Member]
Defined Benefit Pension Plan assets:
Money market funds	5	6
Equity securities:
Domestic	132	146
International equity securities - defined benefit pension plan assets	170	171
Debt securities:
Domestic government and corporate credit	177	197
Private equity funds	0	0
Defined Benefit Plan, Fair Value of Plan Assets	484	520
Other Postretirement Benefit Plans assets: [Abstract]
Money market funds	7	6
Domestic equity securities - Other postretirement benefit plan assets at fair value	10	1
International equity securities - other post retirement assets at fair value	0	0
Debt securities—Domestic government	5	0
Other post retirement benefit plan assets total	22	7
Fair Value, Inputs, Level 3 [Member]
Defined Benefit Pension Plan assets:
Money market funds	0	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
Private equity funds	22	29
Defined Benefit Plan, Fair Value of Plan Assets	22	29	$ 31
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