Schedule VI Supplementary Information Concerning Property and Casualty Insurance Operations (Details) - Property and Casualty Insurance Products - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
SEC Schedule, 12-18, Supplemental Information, Property-Casualty Insurance Underwriters [Line Items]
Discount Deducted From Liabilities	$ 388	$ 388	$ 410
Losses and Loss Adjustment Expenses Incurred Related to: Current Year	7,463	7,107	7,381
Losses and Loss Adjustment Expenses Incurred Related to: Prior Year	(65)	(167)	(41)
Paid Losses and Loss Adjustment Expenses	$ 6,748	$ 6,406	$ 6,579
Financial Guarantee Insurance Contracts, Claim Liability, Weighted Average Risk Free Discount Rate	2.91%	2.98%	3.06%