Acquisitions - (Schedule of Merger Related Costs) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Business Acquisition [Line Items]
Transition Services		$ 18	$ 0
Professional fees (bank, legal, consulting)		1	47
Representation & warranty insurance		0	11
Contract buyouts, terminations and transfers		3	8
Due diligence and environmental		2	4
Employee-related		1	3
Other		2	3
Merger-related expenses	$ 0	27	76
Indigo Merger
Business Acquisition [Line Items]
Transition Services		0	0
Professional fees (bank, legal, consulting)		0	27
Representation & warranty insurance		0	4
Contract buyouts, terminations and transfers		1	7
Due diligence and environmental		1	3
Employee-related		0	2
Other		0	2
Merger-related expenses		2	45
GEPH Merger
Business Acquisition [Line Items]
Transition Services		18	0
Professional fees (bank, legal, consulting)		1	19
Representation & warranty insurance		0	7
Contract buyouts, terminations and transfers		2	1
Due diligence and environmental		1	1
Employee-related		1	0
Other		2	0
Merger-related expenses		$ 25	28
Other
Business Acquisition [Line Items]
Transition Services			0
Professional fees (bank, legal, consulting)			1
Representation & warranty insurance			0
Contract buyouts, terminations and transfers			0
Due diligence and environmental			0
Employee-related			1
Other			1
Merger-related expenses			$ 3