Reserves for Insurance Losses and Loss Adjustment Expenses Reserves for Insurance Losses and Loss Adjustment Expenses (Schedule of Liability for Unpaid Claims and Claims Adjustment Expense) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Liability for Claims and Claims Adjustment Expenses (Rollforward) [Abstract]
Liability for Claims and Claims Adjustment Expense			$ 149	$ 169
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments			108	120
Liability for Unpaid Claims and Claims Adjustment Expense, Net			41	49
Current Year Claims and Claims Adjustment Expense			276	291
Prior Year Claims and Claims Adjustment Expense			2	(4)
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims	$ 65	$ 69	278	287
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Current Year			(248)	(266)
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Prior Years			(31)	(27)
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid			(279)	(293)
Liability for Unpaid Claims and Claims Adjustment Expense, Foreign Currency Translation Gain (Loss)			1	1
Liability for Unpaid Claims and Claims Adjustment Expense, Net	41	44	41	44
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments	132	106	132	106
Liability for Claims and Claims Adjustment Expense	$ 173	$ 150	$ 173	$ 150