Centene Corporation Annual report pursuant to Section 13 and 15(d)

Affordable Care Act (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Affordable Care Act (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018	Dec. 31, 2019
Affordable Care Act [Abstract]
Risk adjustment and reinsurance, pre-tax benefit, period increase (decrease)	$ 131	$ 238
Risk adjustment receivable		91	$ 245
Risk adjustment payable		(1,019)	(1,239)
Minimum medical loss ratio		(265)	(367)
Cost sharing reduction receivable		57	73
Cost sharing reduction payable		$ (107)	$ (1)