Schedule V. Valuation and Qualifying Accounts (Schedule of valuation and qualifying accounts) (Details) - Allowance for doubtful accounts, insurance and reinsurance receivables [Member] - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Movement in valuation allowances and reserves [Roll Forward]
Balance at beginning of period		$ 89	$ 109	$ 155
Charged to costs and expenses		(2)	(12)	(40)
Charged to other accounts	[1]	(1)	0	(1)
Deductions		(3)	(8)	(5)
Balance at end of period		$ 83	$ 89	$ 109

[1] Amount includes effects of foreign currency translation.