Related Party Transactions - Schedule of Related Parties (Detail) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Related Party Transaction [Line Items]
Natural gas purchases (net of sales) from affiliates	$ 65	$ 232	$ 236
Services to/(from) affiliates	28	(4)	(7)
Interest expense to affiliates	239	167	130
Dividends to TECO Energy	472	517	450
Equity contributions from TECO Energy	300	605	580
Affiliate [Member]
Related Party Transaction [Line Items]
Accounts receivable excluding asset management agreements	12	5
Taxes receivable	3	10
Accounts payable	10	31
Note payable to TECO Energy	0	195
Related Party [Member]
Related Party Transaction [Line Items]
Interest income from affiliates	38	0	0
Interest expense to affiliates	11	0	0
Emera Energy Services Inc [Member]
Related Party Transaction [Line Items]
Accounts receivable related to asset management agreements	4	7
TECO Energy [Member]
Related Party Transaction [Line Items]
Dividends to TECO Energy	472	517	450
Equity contributions from TECO Energy	$ 300	$ 605	$ 580

Accounts receivable excluding asset management agreements.

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Natural gas sales to (from) affiliates.

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