Segment Information (Reconciliation Of Reportable Segments Operating Gain To Income Before Income Tax Expense Included In The Consolidated Statements Of Income) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Segment Reporting [Abstract]
Reportable segments operating gain	$ 2,194	$ 1,940
Net investment income	254	210
Net realized (losses) gains on financial instruments	(24)	78
Impairment losses recognized in income	(57)	(10)
Interest expense	(194)	(187)
Amortization of other intangible assets	(83)	(87)
(Loss) gain on extinguishment of debt	(1)	1
Income before income tax expense	$ 2,089	$ 1,945