Reinsurance (Reinsurance amounts recorded on the Consolidated Statement of Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reinsurance [Abstract]
Direct insurance premiums and fee income	$ 11,882	$ 10,103	$ 9,373
Reinsurance assumed	96	101	105
Reinsurance ceded	(1,883)	(1,817)	(1,728)
Total insurance premiums and fee income	10,095	8,387	7,750
Direct insurance benefits	8,513	6,669	6,112
Reinsurance recoveries netted against benefits	(2,369)	(1,851)	(1,865)
Total benefits	$ 6,144	$ 4,818	$ 4,247