Postretirement Benefit Plans (Rollforward of Fair Value Measurements) (Details) - USD ($) $ in Millions |
12 Months Ended | |
---|---|---|
Dec. 31, 2016 |
Dec. 31, 2015 |
|
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||
Beginning Balance | $ 559 | |
Ending Balance | 562 | $ 559 |
Hedge funds | ||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||
Beginning Balance | 181 | |
Ending Balance | 178 | 181 |
Private equity | ||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||
Beginning Balance | 17 | |
Ending Balance | 13 | 17 |
Other | Level 3 | ||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||
Beginning Balance | 25 | 17 |
Purchases, sales, settlements | 1 | 2 |
Net transfers | (7) | |
Impact on currency | (2) | (1) |
Ending Balance | $ 24 | $ 25 |