Income Taxes - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Contingency [Line Items]
Income tax expense related to net gains from sales of investment securities	$ (3,000,000)	$ 5,000,000	$ 6,000,000
Foreign income (loss) before taxes	1,300,000,000	1,330,000,000	$ 1,250,000,000
Unappropriated retained earnings	4,900,000,000
Undistributed earnings of foreign subsidiaries	1,100,000,000
Tax credit carryforwards	2,000,000
Operating loss carryforwards	26,000,000	53,000,000
Operating loss carryforwards that don't expire	19,000,000
Operating loss carryforwards that expire	7,000,000
Operating loss carryforwards valuation allowance	22,000,000	45,000,000
Tax positions for which the ultimate deductibility is highly certain but time is uncertain	55,000,000
Interest accrued for tax examination	3,000,000	9,000,000
Maximum estimated income tax expense change in unrecognized tax benefit in the next 12 months	7,000,000
Interest expense for tax examination	$ 5,000,000	$ 3,000,000