Shareholders' Equity Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2021	Dec. 13, 2019
Class of Warrant or Right [Line Items]
Capital in Excess of Par Value	$ 2,897		$ 2,904
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right		7,777,779
Class of Warrant or Right, Exercise Price of Warrants or Rights		$ 99.96		$ 99.96
Adjustments to Additional Paid in Capital, Stock Issued, Own-share Lending Arrangement, Issuance Costs	$ 2,900
Common Stock, Par or Stated Value Per Share	$ 0.001		$ 0.001	$ 0.001
Common Stock
Class of Warrant or Right [Line Items]
Stock Issued During Period, Shares, New Issues		69,999,954
Warrant [Member]
Class of Warrant or Right [Line Items]
Capital in Excess of Par Value				$ 31
Reorganization Adjustments | Additional Paid-in Capital [Member]
Class of Warrant or Right [Line Items]
Fresh-Start Adjustment, Issuance Of Successor Common Stock To Creditors		$ 2,837