Insurance (Liabilities for Unpaid Claims and Claim Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Balance at December 31 of prior period	$ 1,693	$ 1,483	$ 1,325
Less: Reinsurance recoverables	1,545	1,400	1,235
Net balance at December 31 of prior period	215	83	90
Incurred related to:
Current year	638	105	3
Prior years	(22)	0	2
Total incurred	616	105	5
Paid related to:
Current year	(613)	(30)	0
Prior years	(60)	(10)	(12)
Total paid	(673)	(40)	(12)
Net balance at December 31,	158	215	83
Add: Reinsurance recoverables	1,808	1,545	1,400
Balance at December 31,	1,966	1,693	1,483
Scenario, Previously Reported [Member]
Net balance at December 31 of prior period	148	83	90
Paid related to:
Net balance at December 31,		148	83
Scenario, Adjustment [Member]
Net balance at December 31 of prior period	$ 67	0	0
Paid related to:
Net balance at December 31,		$ 67	$ 0