Condensed Financial Information of Registrant - Condensed Balance Sheets (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 13,118	$ 10,800	$ 12,123
Short-term investments	1,539	1,580
Other current assets	1,602	1,317
Total current assets	28,497	23,393
Long-term investments	14,043	12,853
Other long-term assets	3,781	1,599
Total assets	78,375	68,719
Current liabilities:
Current portion of long-term debt	267	97
Total current liabilities	25,765	21,585
Long-term debt	18,571	16,682
Other long-term liabilities	5,610	2,956
Total liabilities	51,353	42,757
Redeemable noncontrolling interests	82	77
Stockholders' equity:
Preferred stock, $0.001 par value; authorized 10,000 shares; no shares issued or outstanding at December 31, 2021 and December 31, 2020	0	0
Common stock, $0.001 par value; authorized 800,000 shares; 602,704 issued and 582,479 outstanding at December 31, 2021, and 598,249 issued and 581,479 outstanding at December 31, 2020	1	1
Additional paid-in capital	19,672	19,459
Accumulated other comprehensive earnings	77	337
Retained earnings	8,139	6,792
Treasury stock, at cost (20,225 and 16,770 shares, respectively)	(1,094)	(816)
Total Centene stockholders' equity	26,795	25,773
Noncontrolling interest	145	112
Total stockholders' equity	26,940	25,885	$ 12,659	$ 11,013
Total liabilities, redeemable noncontrolling interests and stockholders' equity	78,375	68,719
Parent Company
Current assets:
Cash and cash equivalents	9	668
Short-term investments	1	1
Other current assets	738	24
Total current assets	748	693
Long-term investments	128	129
Investment in subsidiaries	45,117	41,565
Other long-term assets	271	101
Total assets	46,264	42,488
Current liabilities:
Current liabilities	619	133
Current portion of long-term debt	14	0
Total current liabilities	633	133
Long-term debt	18,148	16,393
Other long-term liabilities	461	0
Total liabilities	19,242	16,526
Redeemable noncontrolling interests	82	77
Stockholders' equity:
Preferred stock, $0.001 par value; authorized 10,000 shares; no shares issued or outstanding at December 31, 2021 and December 31, 2020	0	0
Common stock, $0.001 par value; authorized 800,000 shares; 602,704 issued and 582,479 outstanding at December 31, 2021, and 598,249 issued and 581,479 outstanding at December 31, 2020	1	1
Additional paid-in capital	19,672	19,459
Accumulated other comprehensive earnings	77	337
Retained earnings	8,139	6,792
Treasury stock, at cost (20,225 and 16,770 shares, respectively)	(1,094)	(816)
Total Centene stockholders' equity	26,795	25,773
Noncontrolling interest	145	112
Total stockholders' equity	26,940	25,885
Total liabilities, redeemable noncontrolling interests and stockholders' equity	$ 46,264	$ 42,488