Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Effective tax rate	24.40%	29.30%	26.20%	28.00%
Accrued interest	$ 5,000,000		$ 5,000,000
Accrued penalties	0		0
Tax benefit from subsidiary	$ 1,000,000		$ 2,000,000		$ 13,000,000