Reorganization - Additional Information (Detail) - USD ($)		3 Months Ended
	Feb. 07, 2020	Mar. 31, 2020		Feb. 26, 2020	Jan. 23, 2020	Dec. 31, 2019	Mar. 31, 2019	[1]
Reorganization [Line Items]
Percentage of reorganized for equitization of funded debt held by senior secured term lenders.		94.00%
Recovery to the holders of the senior notes, percentage of equity of reorganized		6.00%
Percentage of new common equity interests		6.00%
Letters of credit outstanding		$ 194,000,000
Common stock, shares issued		196,000,000	[1]			196,000,000	184,000,000
Reorganization items		$ 246,000,000
Contractual interest expense		27,000,000
Term Loan Facility [Member] | Tranche D [Member]
Reorganization [Line Items]
Line of credit facility available for capital		44,000,000
Debtor in Possession [Member]
Reorganization [Line Items]
Reorganization items		246,000,000
DIP Credit Facility fees		87,000,000
DIP Credit Facility professional fees		58,000,000
Term Facility [Member]
Reorganization [Line Items]
Liabilities subject to compromise allowed claims		72,000,000
Prepetition Secured Letters of Credit [Member]
Reorganization [Line Items]
Available capacity under credit facility		50,000,000
Revolving Credit Facility [Member]
Reorganization [Line Items]
Liabilities subject to compromise allowed claims		24,000,000
Minimum [Member]
Reorganization [Line Items]
Cash balances		$ 820,000,000
Maximum [Member]
Reorganization [Line Items]
Projected to receive, percentage of claim		100.00%
Lummus Technology [Member]
Reorganization [Line Items]
Amount paid to acquire bid		$ 2,725,000,000
Incremental costs included in reorganization items		19,000,000
Lummus Technology [Member] | Debtors [Member] | Minimum [Member]
Reorganization [Line Items]
Cash balances		820,000,000
DIP Credit Agreement [Member]
Reorganization [Line Items]
Available capacity under credit facility		2,810,000,000
DIP Credit Agreement [Member] | Term Loan Exit Facility [Member]
Reorganization [Line Items]
Letter of credit / term loan facility		500,000,000
DIP Credit Agreement [Member] | Term Loan Facility [Member]
Reorganization [Line Items]
Available capacity under credit facility		2,065,000,000
Line of credit facility available for capital		800,000,000
Line of credit facility accrued interest and fee		21,000,000
DIP Credit Agreement [Member] | Term Loan Facility [Member] | Tranche A [Member] | Available at Closing [Member]
Reorganization [Line Items]
Line of credit facility available for capital		550,000,000			$ 550,000,000
DIP Credit Agreement [Member] | Term Loan Facility [Member] | Tranche B [Member] | Available upon Entry of Final DIP Order [Member]
Reorganization [Line Items]
Line of credit facility available for capital		650,000,000		$ 650,000,000
DIP Credit Agreement [Member] | Term Loan Facility [Member] | Tranche C [Member]
Reorganization [Line Items]
Line of credit facility available for capital		11,000,000
DIP Credit Agreement [Member] | Letter of Credit Facility [Member]
Reorganization [Line Items]
Letters of credit outstanding		743,000,000,000
Commitments under LC exit facilities and cash secured LC exit facility		2,400,000
DIP Credit Agreement [Member] | Letter of Credit Facility [Member] | Tranche A [Member] | Available at Closing [Member]
Reorganization [Line Items]
Letters of credit outstanding		300,000,000			$ 300,000,000
DIP Credit Agreement [Member] | Letter of Credit Facility [Member] | Tranche B [Member] | Available upon Entry of Final DIP Order [Member]
Reorganization [Line Items]
Letters of credit outstanding		243,000,000		$ 243,000,000
DIP Credit Agreement [Member] | Letter of Credit Facility [Member] | Tranche C [Member]
Reorganization [Line Items]
Letters of credit outstanding		200,000,000
DIP Credit Agreement [Member] | Letter of Credit Facility [Member] | Tranche D [Member]
Reorganization [Line Items]
Letters of credit outstanding		743,000,000
DIP Credit Agreement [Member] | Letter of Credit Facility [Member] | Super Senior Exit Facility [Member]
Reorganization [Line Items]
Letter of credit / term loan facility		743,000,000
DIP Credit Agreement [Member] | Maximum [Member] | Letter of Credit Facility [Member] | Senior LC Exit Facility [Member]
Reorganization [Line Items]
Letter of credit / term loan facility		1,326,000
DIP Credit Agreement [Member] | Maximum [Member] | Letter of Credit Facility [Member] | Cash Secured LC Exit Facility [Member]
Reorganization [Line Items]
Letter of credit / term loan facility		371,000,000
Share and asset purchase agreement [Member]
Reorganization [Line Items]
Amount paid to acquire bid		$ 2,725,000,000
Restructuring Support Agreement [Member] | Rights Offering [Member]
Reorganization [Line Items]
Subscriptions	$ 0
Common stock, shares issued	0
Rights offering expiration date	Feb. 19, 2020

[1] ^{Amounts in this table may not sum due to rounding.}