Investments in Unconsolidated Affiliates (Tables)

12 Months Ended

Dec. 31, 2020

Equity Method Investments and Joint Ventures [Abstract]

Investments in Equity Method Unconsolidated Affiliates

The following table presents Duke Energy’s investments in unconsolidated affiliates accounted for under the equity method, as well as the respective equity in earnings, by segment.

	Years Ended December 31,
	2020				2019				2018
			Equity in				Equity in				Equity in
(in millions)	Investments		earnings		Investments		earnings		Investments		earnings
Electric Utilities and Infrastructure	$	105	$	(1)	$	122	$	9	$	97	$	6
Gas Utilities and Infrastructure	215		(2,017)		1,388		114		1,003		27
Commercial Renewables	534		—		314		(4)		201		(1)
Other	107		13		112		43		108		51
Total	$	961	$	(2,005)	$	1,936	$	162	$	1,409	$	83

The table below outlines Duke Energy's ownership interests in natural gas pipeline companies and natural gas storage facilities.

			Investment Amount (in millions)
	Ownership		December 31,
Entity Name	Interest		2020		2019
Pipeline Investments(a)
ACP(b)	47	%	$	—	$	1,179
Sabal Trail	7.5	%	120		121
Cardinal(c)	21.49	%	9		9
Storage Facilities
Pine Needle(c)	45	%	27		28
Hardy Storage(c)	50	%	56		51
Other	29.68	%	3		—
Total Investments(d)			$	215	$	1,388

(a)    Duke Energy recorded OTTIs of $25 million and $55 million within Equity in (losses) earnings of unconsolidated affiliates on Duke Energy's Consolidated Statements of Operations for the years ended December 31, 2019, and 2018, respectively, to completely impair its 24% ownership interest in Constitution.

(b)    In 2020, Duke Energy determined it would no longer continue its investment in the construction of the ACP pipeline. See Notes 3 and 7 for further information.

(c)    Piedmont owns the Cardinal, Pine Needle and Hardy Storage investments.

(d)    Duke Energy includes purchase accounting adjustments related to Piedmont.

For the year ended December 31, 2020, Duke Energy's investment in ACP met the requirements of S-X Rule 4-08(g) to provide summarized financial information. The following table provides summary information for ACP as required under S-X Rule 1-02(bb) for the comparative periods in Duke Energy's consolidated balance sheets and consolidated statements of operations.

			December 31,
(in millions)			2020		2019
Current assets			$	43	$	17
Noncurrent assets			93		4,091
Current liabilities			1,965		37
Noncurrent liabilities			167		1,760
Membership interests			(1,996)		2,311
	Years Ended December 31,
	2020		2019		2018
Net revenues	$	—	$	—	$	—
Operating loss	(4,612)		(5)		(6)
Net (loss) income	(4,512)		246		138
Net (loss) income attributable to Duke Energy	$	(2,121)	$	116	$	65