Pension and Postretirement Expense Level 4 (Details) - U.S. Pension Plan Investments Measured at Fair Value - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
investment receivable	$ 12	$ 0
United States Pension Plans of US Entity, Defined Benefit [Member]
Large Cap Equity Funds	35	38
Small mid Cap Equity Funds	6	5
Other International Equity	25	25
Debt Securities Fixed Income	110	114
Cash, Money Market and Other	4	3
Pension Benefits Fair Value of Plan Assets of Underfunded Plans	207	210
Fair value of plan assets at end of year subtotal	180	185
Other funds	15	25
United States Pension Plans of US Entity, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member]
Large Cap Equity Funds	0	0
Small mid Cap Equity Funds	0	0
Other International Equity	0	0
Debt Securities Fixed Income	0	0
Cash, Money Market and Other	0	0
Pension Benefits Fair Value of Plan Assets of Underfunded Plans	0	0
United States Pension Plans of US Entity, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member]
Large Cap Equity Funds	35	38
Small mid Cap Equity Funds	6	5
Other International Equity	25	25
Debt Securities Fixed Income	110	114
Cash, Money Market and Other	4	3
Pension Benefits Fair Value of Plan Assets of Underfunded Plans	180	185
United States Pension Plans of US Entity, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member]
Large Cap Equity Funds	0	0
Small mid Cap Equity Funds	0	0
Other International Equity	0	0
Debt Securities Fixed Income	0	0
Cash, Money Market and Other	0	0
Pension Benefits Fair Value of Plan Assets of Underfunded Plans	$ 0	$ 0