Derivative Instruments and Hedging Activities - Commodity Purchases (Details) - Not Designated As Hedging Instruments [Member] - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Commodity Purchases [Line Items]
Liability value	$ 34	$ 67
Asset value	2	1
Other Current Assets
Commodity Purchases [Line Items]
Asset value	2	1
Other Current Assets | Gas Contract
Commodity Purchases [Line Items]
Asset value	2	1
Other Current Assets | Interest Rate Swaps [Member]
Commodity Purchases [Line Items]
Asset value	0	0
Other Current Liabilities
Commodity Purchases [Line Items]
Liability value	23	52
Other Current Liabilities | Gas Contract
Commodity Purchases [Line Items]
Liability value	22	51
Other Current Liabilities | Interest Rate Swaps [Member]
Commodity Purchases [Line Items]
Liability value		1
Other Noncurrent Assets [Member]
Commodity Purchases [Line Items]
Asset value	0	0
Other Noncurrent Assets [Member] | Gas Contract
Commodity Purchases [Line Items]
Asset value	0	0
Other Noncurrent Assets [Member] | Interest Rate Swaps [Member]
Commodity Purchases [Line Items]
Asset value	0	0
Other Noncurrent Liabilities
Commodity Purchases [Line Items]
Liability value	11	15
Other Noncurrent Liabilities | Gas Contract
Commodity Purchases [Line Items]
Liability value	$ 5	9
Other Noncurrent Liabilities | Interest Rate Swaps [Member]
Commodity Purchases [Line Items]
Liability value		$ 6