Reserves for Insurance Losses and Loss Adjustment Expenses Reserves for Insurance Losses and Loss Adjustment Expenses (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Reserves for Insurance Losses and Loss Adjustment Expense [Abstract]
Liability for Claims and Claims Adjustment Expense	$ 140	$ 149
Reinsurance Recoverable for Paid and Unpaid Claims and Claims Adjustments	108	108
Liability for Unpaid Claims and Claims Adjustment Expense, Net	32	41
Current Year Claims and Claims Adjustment Expense	60	89
Prior Year Claims and Claims Adjustment Expense	3	(1)
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims	63	88
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Current Year	31	45
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Prior Years	19	23
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid	50	68
Liability for Unpaid Claims and Claims Adjustment Expense, Foreign Currency Translation Gain (Loss)	0	2
Liability for Unpaid Claims and Claims Adjustment Expense, Net	45	63
Reinsurance Recoverable for Paid and Unpaid Claims and Claims Adjustments	112	112
Liability for Claims and Claims Adjustment Expense	$ 157	$ 175