Reorganization Expense (Details) - USD ($) $ in Millions		6 Months Ended		12 Months Ended
	Jul. 01, 2019	Dec. 31, 2019	Jun. 30, 2019	Dec. 31, 2018	Dec. 31, 2017
Reorganization Items, net [Abstract]
Gain on reorganization adjustments		$ 0	$ (1,254)
Gain on fresh start adjustments		0	(2,007)
Debtor Reorganization Items, Other Expense (Income)		0	104
Debtor Reorganization Items, Legal and Advisory Professional Fees	$ 39	0	39
Debtor Reorganization Items, Debtor-in-Possession Facility Financing Costs		0	13
Reorganization Items		$ 0	$ (3,105)	$ 0	$ 0