Deferred Policy Acquisition Costs - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Deferred Policy Acquisition Costs Disclosures [Abstract]
Accumulated amortization of present value of future profits	$ 134	$ 125
Approximate annual rate of decrease in present value of future profits during next five years	0.167