Segment Information - Additional Information (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2020 USD ($) segment	Mar. 31, 2019 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment	2
Revenues | $	$ 1,789	$ 1,842
Networks
Segment Reporting Information [Line Items]
Number of reportable segments | segment	1
Number of operating segments | segment	8
Revenues | $	$ 1,461	1,604
Renewables
Segment Reporting Information [Line Items]
Revenues | $	$ 328	$ 242