Medical Claims Payable (Reconciliation Of The Beginning And Ending Balances For Medical Claims Payable By Segment) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Medical Claims Payable [Line Items]
Gross medical claims payable, beginning of period	$ 13,282	$ 11,135
Ceded medical claims payable, beginning of period	(21)	(46)
Net medical claims payable, beginning of period	13,261	11,089
Business combinations and purchase adjustments	3
Current period net incurred medical claims	28,064	24,215
Prior periods redundancies	(933)	(1,488)
Total net incurred medical claims	27,131	22,727
Net payments attributable to current period medical claims	17,116	15,031
Net payments attributable to prior periods medical claims	8,826	6,748
Total net payments	25,942	21,779
Net medical claims payable, end of period	14,453	12,037
Ceded medical claims payable, end of period	17	39
Gross medical claims payable, end of period	14,470	12,076
Commercial & Specialty Business Segment [Member]
Medical Claims Payable [Line Items]
Gross medical claims payable, beginning of period	3,847	3,294
Ceded medical claims payable, beginning of period	(13)	(13)
Net medical claims payable, beginning of period	3,834	3,281
Business combinations and purchase adjustments	3
Current period net incurred medical claims	7,070	6,575
Prior periods redundancies	(236)	(503)
Total net incurred medical claims	6,834	6,072
Net payments attributable to current period medical claims	4,571	4,164
Net payments attributable to prior periods medical claims	2,232	1,746
Total net payments	6,803	5,910
Net medical claims payable, end of period	3,868	3,443
Ceded medical claims payable, end of period	9	9
Gross medical claims payable, end of period	3,877	3,452
Government Business Segment [Member]
Medical Claims Payable [Line Items]
Gross medical claims payable, beginning of period	9,157	7,646
Ceded medical claims payable, beginning of period	(8)	(33)
Net medical claims payable, beginning of period	9,149	7,613
Business combinations and purchase adjustments	0
Current period net incurred medical claims	20,586	17,289
Prior periods redundancies	(643)	(970)
Total net incurred medical claims	19,943	16,319
Net payments attributable to current period medical claims	12,331	10,650
Net payments attributable to prior periods medical claims	6,457	4,856
Total net payments	18,788	15,506
Net medical claims payable, end of period	10,304	8,426
Ceded medical claims payable, end of period	8	30
Gross medical claims payable, end of period	10,312	8,456
Other Segment [Member]
Medical Claims Payable [Line Items]
Gross medical claims payable, beginning of period	278	195
Ceded medical claims payable, beginning of period	0	0
Net medical claims payable, beginning of period	278	195
Business combinations and purchase adjustments	0
Current period net incurred medical claims	408	351
Prior periods redundancies	(54)	(15)
Total net incurred medical claims	354	336
Net payments attributable to current period medical claims	214	217
Net payments attributable to prior periods medical claims	137	146
Total net payments	351	363
Net medical claims payable, end of period	281	168
Ceded medical claims payable, end of period	0	0
Gross medical claims payable, end of period	$ 281	$ 168