Variable Interest Entities (Detail) $ in Millions		3 Months Ended
	Mar. 02, 2020 USD ($) wind_farm MW	Mar. 31, 2020 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2019 USD ($)
Variable Interest Entity [Line Items]
Contributions from noncontrolling interests	$ 237	$ 244	$ 3
Wind firms that reached commercial operation | wind_farm	2
Wind farms expected to be part of Aeolus VII | wind_farm	4
Proposed wind farm and electricity transmission project capacity (MW) | MW	681
Assets of variable interest entities (VIEs)		34,593		$ 34,416
Liabilities of variable interest entities (VIEs)		18,685		18,830
Equity method investments of variable interest entities (VIEs)		656		645
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Assets of variable interest entities (VIEs)		1,497		806
Liabilities of variable interest entities (VIEs)		$ 56		$ 29