CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Unrealized gains (losses) on derivatives, tax	$ (2)	$ 3	$ 2
Pension and postretirement gains, tax	(27)	44	(101)
Inventory adjustment for hedged natural gas	(2)
Reclassification to income of realized losses on derivatives, tax	$ (1)	(5)	$ 2
Distribution of stock of subsidiary to shareholders, tax		$ 14