Stockholders' Equity (Details) - USD ($)		12 Months Ended
	Jan. 23, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Feb. 28, 2021	Oct. 31, 2019	Dec. 31, 2011
Subsidiary, Sale of Stock [Line Items]
Preferred stock, shares authorized (in shares)		10,000,000	10,000,000
Preferred stock, par value (in usd per share)		$ 0.001	$ 0.001
Preferred stock, shares outstanding (in shares)		0	0
Stock repurchase program, shares authorized to repurchase (in shares)					1,000,000,000		16,000,000
Stock repurchase program increase amount						$ 500,000,000
Centene closing stock price (in usd per share)	$ 66.76					$ 66.76
Stock repurchase program, additional shares authorized to be repurchased (in shares)						7,500,000
Remaining number of shares available to be repurchased (in shares)		800,000,000
Common stock repurchases (in shares)		(2,400,000)	(8,700,000)
Common stock repurchases		$ 297,000,000	$ 626,000,000	$ 75,000,000
Aggregate cost of shares withheld		$ 297,000,000	$ 626,000,000	$ 75,000,000
WellCare
Subsidiary, Sale of Stock [Line Items]
Shares issued in business acquisition (in shares)	171,000,000
Equity value issued in business acquisition	$ 11,431,000,000
Cash payments to acquire business	6,079,000,000
Fair value adjustment to stock based compensation associated with pre-combination service	$ 95,000,000
Common Stock
Subsidiary, Sale of Stock [Line Items]
Common stock repurchases (in shares)		(326,000)	(407,000)
Common stock repurchases		$ 200,000,000	$ 500,000,000
Employee Stock Compensation Plan
Subsidiary, Sale of Stock [Line Items]
Common stock repurchases (in shares)		(1,100,000)	(1,600,000)
Common stock repurchases		$ 78,000,000	$ 102,000,000
Shares withheld for tax withholding obligation (in shares)		326,000	407,000
Aggregate cost of shares withheld		$ 19,000,000	$ 24,000,000