CONTINGENCIES AND COMMITMENTS (Detail) - USD ($)		9 Months Ended
	Oct. 10, 2013	Sep. 30, 2019	Dec. 31, 2018
Loss Contingencies [Line Items]
Malpractice Loss Contingency, Claims Incurred in Period		$ 400,000,000
Standby Letters Of Credit [Member]
Loss Contingencies [Line Items]
Letters of credit, outstanding		29,100,000	$ 21,700,000
FinancialStandbyLetterOfCreditMember
Loss Contingencies [Line Items]
Letters of credit, outstanding		10,200,000	$ 11,700,000
Failure to Meet Contractual Obligations [Member]
Loss Contingencies [Line Items]
Damages sought	$ 25,000,000
Surety Bond [Member]
Loss Contingencies [Line Items]
Surety Bond Outstanding		45,600,000
Damage from Fire, Explosion or Other Hazard [Member]
Loss Contingencies [Line Items]
Estimated Litigation Liability		1,000,000,000
Minimum [Member]
Loss Contingencies [Line Items]
Range of possible loss		0
Maximum [Member]
Loss Contingencies [Line Items]
Range of possible loss		55,500,000
AP1000 US [Member] | Minimum [Member]
Loss Contingencies [Line Items]
Range of possible loss		0
AP1000 US [Member] | Maximum [Member]
Loss Contingencies [Line Items]
Range of possible loss		$ 31,000,000