Business Combination - Composition of Consideration (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions						12 Months Ended
		Jul. 16, 2021	Jul. 16, 2020	Jul. 16, 2018	Oct. 06, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition, Contingent Consideration [Line Items]
Deferred consideration for acquisition of Centaur						$ 66	$ 0	$ 0
Payments for Restructuring					$ 3,487
Stock Issued During Period for Merger and Emergence					8,103
Business Combination, Settlement of pre-existing relationship					252
Business Acquisition, Equity Interest Issued or Issuable, Value Assigned					$ 2,726
Stock Issued During Period, Shares, Other					633
Centaur Holdings, LLC [Member]
Business Acquisition, Contingent Consideration [Line Items]
Cash paid				$ 1,636
Deferred consideration for acquisition of Centaur	[1]			66
Business Combination, Consideration Transferred				$ 1,702
OpCo [Member]
Business Acquisition, Contingent Consideration [Line Items]
Business Combination, Consideration Transferred					$ 2,474
Payments for Restructuring					700
Stock Issued During Period for Merger and Emergence	[2]				$ 1,774
Shares Issued, Price Per Share					$ 12.80
Stock Issued During Period, Shares, Other					139
Scenario, Forecast [Member] | Centaur Holdings, LLC [Member]
Business Acquisition, Contingent Consideration [Line Items]
Business Combination Deferred Consideration Face Value		$ 50	$ 25

[1] (1) Deferred consideration is payable in an installment of $25 million on the second anniversary of the Centaur Closing Date and $50 million on the third anniversary of the Centaur Closing Date with prepayments and right of setoff permitted, subject to the terms and conditions of the Unit Purchase Agreement. $66 million represents the present value of future expected cash flows.

[2] (1) Approximately 139 million shares of CEC common stock issued at the Effective Date closing stock price of $12.80.