Basis of Presentation (Details) - USD ($) $ in Millions	3 Months Ended
	Sep. 30, 2017	Mar. 31, 2017
Income tax provision [Member]
Quantifying Misstatement in Current Year Financial Statements [Line Items]
Quantifying misstatement in current year financial statements, amount		$ (20)
Pretax income [Member]
Quantifying Misstatement in Current Year Financial Statements [Line Items]
Quantifying misstatement in current year financial statements, amount	$ (14)
Amortization of deferred acquisition costs [Member]
Quantifying Misstatement in Current Year Financial Statements [Line Items]
Quantifying misstatement in current year financial statements, amount	(10)
Benefits, claims, losses and settlement expenses [Member]
Quantifying Misstatement in Current Year Financial Statements [Line Items]
Quantifying misstatement in current year financial statements, amount	$ (4)