CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (PARENTHETICAL) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS)
Unrealized gains (losses) designated cash flow and net investment hedges, tax (expense) benefit	$ 0	$ 0	$ 0
Unrealized gains (losses) on investments, tax (expense) benefit	0	0	2
Reclassification of realized net losses (gains) to net income, tax expense (benefit)	0	0	0
Pension adjustment, tax (expense) benefit	$ 4	$ 1	$ 32