Postretirement Benefit Plans (Textuals) (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
---|---|---|---|---|
Jun. 30, 2017 |
Jun. 30, 2016 |
Jun. 30, 2017 |
Jun. 30, 2016 |
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Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block | ||||
Other postretirement benefit expense (less than $1 million for the three months ended June 30, 2017) | $ 1 | $ 1 | $ 1 | $ 2 |
Amortization of net actuarial loss (less than $1 million) | 1 | $ 1 | 1 | 1 |
Employer contribution to defined benefit plan | 13 | $ 14 | ||
Minimum | ||||
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block | ||||
Additional contributions | 9 | 9 | ||
Maximum | ||||
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block | ||||
Additional contributions | $ 15 | $ 15 |