Reinsurance (Reinsurance amounts recorded on the Consolidated Statement of Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reinsurance [Abstract]
Direct insurance premiums and fee income	$ 9,551	$ 9,529	$ 9,064
Reinsurance assumed	93	73	7
Reinsurance ceded	(1,413)	(1,311)	(1,410)
Total insurance premiums and fee income	8,231	8,291	7,661
Direct insurance benefits	6,195	6,420	6,127
Reinsurance recoveries netted against benefits	(1,503)	(1,376)	(1,448)
Benefits	$ 4,692	$ 5,044	$ 4,679