SCHEDULE VI - SUPPLEMENTARY INFORMATION CONCERNING CONSOLIDATED PROPERTY-CASUALTY INSURANCE OPERATIONS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Supplemental Information for Property, Casualty Insurance Underwriters [Abstract]
Deferred policy acquisition costs	$ 2,188	$ 2,029	$ 1,820
Reserves for insurance claims and claims expense	25,250	23,869	22,923
Unearned premiums	12,571	12,189	11,640
Earned premiums	31,307	30,309	28,929
Net investment income	1,266	1,237	1,301
Claims and claims adjustment expense incurred
Current year	22,238	20,953	19,512
Prior years	(17)	(81)	(84)
Amortization of deferred policy acquisition costs	4,267	4,102	3,875
Paid claims and claims adjustment expense	21,132	20,286	19,392
Premiums written	$ 31,600	$ 30,871	$ 29,614