Investments (Unconsolidated Equity Investments) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Schedule of Equity Method Investments [Line Items]
Carrying value	$ 542	$ 508	$ 476
Equity (income) / loss	(51)	(62)	(61)
ATC Holdings [Member]
Schedule of Equity Method Investments [Line Items]
Carrying value	358	338
Equity (income) / loss	$ (41)	(43)	(47)
ATC LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest	16.00%
ATC Holdco LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest	20.00%
Non-utility wind farm in Oklahoma [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest	50.00%
Carrying value	$ 101	99
Equity (income) / loss	(5)	(4)	(8)
Corporate venture investments [Member]
Schedule of Equity Method Investments [Line Items]
Carrying value	62	52
Equity (income) / loss	(3)	(13)	(4)
Other [Member]
Schedule of Equity Method Investments [Line Items]
Carrying value	21	19
Equity (income) / loss	(2)	(2)	(2)
Total [Member]
Schedule of Equity Method Investments [Line Items]
Carrying value	542	508
Equity (income) / loss	$ (51)	$ (62)	$ (61)