Segments of Operations - Assets by segment and sub-segment (Details) - USD ($) $ in Millions		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Total assets		$ 55,072	$ 49,837	$ 47,513
Property and casualty insurance
Segment Reporting Information [Line Items]
Total assets	[1]	15,574	14,689	14,069
Annuity
Segment Reporting Information [Line Items]
Total assets		33,409	29,865	27,317
Run-off long-term care and life
Segment Reporting Information [Line Items]
Total assets	[2]	752	772	2,489
Other
Segment Reporting Information [Line Items]
Total assets		$ 5,337	$ 4,511	$ 3,638

[1] Not allocable to sub-segments.

[2] AFG sold substantially all of its run-off long-term care insurance business in December 2015.