Segments of Operations (Details Textual) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2016 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($) segment	Jun. 30, 2015 USD ($)
Segment Reporting Information [Line Items]
Number of segments | segment				4
Other income		$ 80	$ 92	$ 126	$ 142
Special charges related to the exit of certain lines of business within subsidiaries		65
Property and Casualty Insurance [Member]
Segment Reporting Information [Line Items]
Other income	[1]	40	53	$ 43	$ 59
Property and Casualty Insurance [Member] | Real Estate Investment [Member]
Segment Reporting Information [Line Items]
Other income		32	$ 51
Other Lines [Member]
Segment Reporting Information [Line Items]
Special charges related to the exit of certain lines of business within subsidiaries		$ 65

[1] Includes pretax income of $32 million (before noncontrolling interest) from the sale of an apartment property in the second quarter of 2016 and $51 million (before noncontrolling interest) from the sale of the Le Pavillon Hotel in the second quarter of 2015.