Segment Information (Reconciliation Of Revenue From Reportable Segments To The Consolidated Statements Of Income) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting, Revenue Reconciling Item [Line Items]
Reportable segments operating revenues									$ 103,141	$ 91,341	$ 89,061
Net investment income									1,005	970	867
Net realized gains (losses) on financial instruments									114	(180)	145
Other-than-temporary impairment losses recognized in income									(47)	(26)	(33)
Total revenues	$ 27,407	$ 26,674	$ 25,466	$ 24,666	$ 23,373	$ 23,251	$ 22,944	$ 22,537	$ 104,213	$ 92,105	$ 90,040