Claim and Claim Adjustment Expense Reserves Short Duration Contracts – Net Strengthening or Releasing of Prior Accident Year Reserves - International - Hardy (Details) - Hardy [Member] - USD ($) $ in Millions	12 Months Ended					24 Months Ended	36 Months Ended	48 Months Ended	60 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2016
Short-duration Insurance Contracts, Accident Year 2007 [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Net Prior Year Claim and Allocated Claim Adjustment Expense Reserve Development	$ 5	$ (6)	$ 5	$ (1)	$ 7				$ 10
Short-duration Insurance Contracts, Accident Year 2008 [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Net Prior Year Claim and Allocated Claim Adjustment Expense Reserve Development	0	1	1	(3)	(4)				(5)
Short-duration Insurance Contracts, Accident Year 2009 [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Net Prior Year Claim and Allocated Claim Adjustment Expense Reserve Development	(3)	5	(10)	(6)	1				(13)
Short-duration Insurance Contracts, Accident Year 2010 [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Net Prior Year Claim and Allocated Claim Adjustment Expense Reserve Development	6	(6)	4	10	(10)				4
Short-duration Insurance Contracts, Accident Year 2011 [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Net Prior Year Claim and Allocated Claim Adjustment Expense Reserve Development	(2)	4	0	9	$ 0				$ 11
Short-duration Insurance Contracts, Accident Year 2012 [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Net Prior Year Claim and Allocated Claim Adjustment Expense Reserve Development	(7)	7	8	$ 0				$ 8
Short-duration Insurance Contracts, Accident Year 2013 [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Net Prior Year Claim and Allocated Claim Adjustment Expense Reserve Development	1	(8)	$ 17				$ 10
Short-duration Insurance Contracts, Accident Year 2014 [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Net Prior Year Claim and Allocated Claim Adjustment Expense Reserve Development	(6)	$ (2)				$ (8)
Short-duration Insurance Contracts, Accident Year 2015 [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Net Prior Year Claim and Allocated Claim Adjustment Expense Reserve Development	$ (11)