Reinsurance (Reinsurance Amounts Recorded on Consolidated Statements of 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	$ 12,041	$ 10,269	$ 9,551
Reinsurance assumed	89	91	93
Reinsurance ceded	(1,543)	(1,485)	(1,413)
Total insurance premiums and fee income	10,587	8,875	8,231
Direct insurance benefits	8,592	6,770	6,195
Reinsurance recoveries netted against benefits	(1,806)	(1,610)	(1,503)
Benefits	$ 6,786	$ 5,160	$ 4,692