Fair Value Measurements - Narrative (Details)	12 Months Ended
	Dec. 31, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notice required to change policyholders' funds interest crediting rate	30 days
Minimum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated liquidation period of underlying assets of the funds	1 year
Maximum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated liquidation period of underlying assets of the funds	10 years