Income Taxes - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income tax expense related to net gains from sales of investment securities	$ 4,000,000	$ (3,000,000)	$ 5,000,000
Foreign income (loss) before taxes	1,220,000,000	1,300,000,000	$ 1,330,000,000
Unappropriated retained earnings	5,500,000,000
Tax expense if unappropriated foreign earnings repatriated	1,100,000,000
Tax credit carryforwards	425,000,000	0
Tax credit carryforwards subject to expiration	406,000,000
Operating loss carryforwards	46,000,000	26,000,000
Operating loss carryforwards that don't expire	31,000,000
Operating loss carryforwards subject to expiration	15,000,000
Operating loss carryforwards valuation allowance	38,000,000	22,000,000
Unrecognized tax benefits that would impact effective tax rate	63,000,000
Interest accrued for tax examination	5,000,000	3,000,000
Maximum estimated income tax expense change in unrecognized tax benefit in the next 12 months	14,000,000
Benefit if maximum estimated income tax expense change in unrecognized tax benefit recognized in the next 12 months	5,000,000
Interest expense for tax examination	$ 2,000,000	$ 5,000,000