Insurance (Obligations Under Funding Agreements - Narrative) (Details) - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Insurance [Abstract]
Funding agreements issued to certain SPEs	$ 37.3	$ 41.8	$ 42.7
Funding agreements repaid to certain SPEs	36.4	43.7	$ 41.4
Outstanding funding agreements to certain SPEs	$ 34.6	$ 32.3