Acquisitions, Development and Divestures (Details) $ in Millions		6 Months Ended		12 Months Ended
	Mar. 31, 2022 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2021 GBP (£)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Jun. 14, 2021 USD ($)
Development Projects [Abstract]
Income (Loss) from Discontinued Operations (net of income taxes)				$ (1,498)	$ 829	$ 1,010
Total current assets held for sale				0	18,983
Total current liabilities held for sale				0	11,023
Forecast [Member]
Development Projects [Abstract]
Payments to Acquire Businesses, Gross	$ 3,800
WPD [Member]
Development Projects [Abstract]
Income tax related to Discontinued Operations				759	188	226
WPD [Member] | Discontinued Operations, Held-for-sale
Development Projects [Abstract]
Loss on Sale				(1,609)	0	0
Operating Revenues related to discontinued operations				1,344	2,133	2,167
Operating Expense related to discontinued operations				467	916	853
Other Income (Expense) - net related to discontinued operations				202	167	295
Interest Expense related to discontinued operations				209	367	373
Income from Discontinued Operations, before Income Tax				870	1,017	1,236
Income tax related to Discontinued Operations				759	188	226
Income (Loss) from Discontinued Operations (net of income taxes)				$ (1,498)	829	$ 1,010
Cash and Cash Equivalents from Disposal Group					266
Accounts receivable and unbilled revenues from Disposal Group					389
Property, Plant and Equipment, net from Disposal Group					14,392
Other intangibles from Disposal Group					413
Price risk management assets from Disposal Group					146
Goodwill from Disposal Group					2,558
Pension benefit asset from Disposal Group					682
Other Assets from Disposal Group					137
Total current assets held for sale					18,983
Short-Term Debt and Long-Term Debt due within one year from Disposal Group					994
Accounts Payable from Disposal Group					220
Customer Deposits from Disposal Group					217
Accrued Interest from Disposal Group					190
Long-term Debt from Disposal Group					7,938
Total deferred income taxes from Disposal Group					1,032
Price risk management liabilities from Disposal Group					137
Other deferred credits and liabilities from Disposal Group					295
Total current liabilities held for sale					11,023
Net Assets from Disposal Group					7,960
Unrealized foreign currency hedge losses recognized in 2020					125
Costs to sell		$ 69
Carrying Value							$ 12,397
Sale proceeds, net of realized foreign currency hedge losses		10,732	£ 7,800,000,000
Proceeds from Daily Dividend, Divestiture of Business | £			548,000
Proceeds from Divestiture of Businesses, before Foreign Currency Hedge Losses | £			£ 7,881,000,000
Disposal Group, Including Discontinued Operation, Loss on Foreign Currency Hedge Against Sale or Disposition		386
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI for Sale of Disposal Group, Net of Tax					$ 4,000		$ 3,600
Net Proceeds From Divestiture Of Businesses		$ 10,400