Segments of Operations (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Segment Reporting Information [Line Items]
Total assets	$ 47,535		$ 42,087		$ 39,171
Property and Casualty Insurance [Member]
Segment Reporting Information [Line Items]
Total assets	14,069	[1]	11,717	[1]	12,163	[1]
Annuity [Member]
Segment Reporting Information [Line Items]
Total assets	27,317		24,294		20,909
Run-off Long-term Care and Life [Member]
Segment Reporting Information [Line Items]
Total assets	2,489		2,408		2,304
Other [Member]
Segment Reporting Information [Line Items]
Total assets	$ 3,660		$ 3,668		$ 3,795

[1] Not allocable to sub-segments.