Description of Business	6 Months Ended
Jun. 30, 2026
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	DESCRIPTION OF BUSINESS Nature of Operations Fortis Inc. ("Fortis" or the "Corporation") is a diversified North American regulated electric and gas utility holding company. Earnings for interim periods may not be indicative of annual results due to: (i) the impact of seasonal weather conditions on customer demand; (ii) the impact of market conditions, particularly with respect to long-term wholesale sales at UNS Energy; (iii) the timing and significance of any regulatory decisions; and (iv) changes in the U.S. dollar-to-Canadian dollar exchange rate. Earnings for the utilities in Canada and New York tend to be highest in the first and fourth quarters due to space-heating requirements. Earnings for UNS Energy tend to be highest in the second and third quarters due to the use of air conditioning and other cooling equipment. Entities within the reporting segments that follow operate with substantial autonomy. Regulated Utilities ITC: ITC Investment Holdings Inc., ITC Holdings Corp. and the electric transmission operations of its regulated operating subsidiaries, which include International Transmission Company, Michigan Electric Transmission Company, LLC, ITC Midwest LLC and ITC Great Plains, LLC. Fortis owns 80.1% of ITC and an affiliate of GIC Private Limited owns a 19.9% minority interest. UNS Energy: UNS Energy Corporation, which primarily includes Tucson Electric Power Company ("TEP"), UNS Electric, Inc. ("UNS Electric") and UNS Gas, Inc. ("UNS Gas"). Central Hudson: CH Energy Group, Inc., which primarily includes Central Hudson Gas & Electric Corporation. FortisBC Energy: FortisBC Energy Inc. FortisAlberta: FortisAlberta Inc. FortisBC Electric: FortisBC Inc. Other Electric: Eastern Canadian and Caribbean utilities, as follows: Newfoundland Power Inc.; Maritime Electric Company, Limited; FortisOntario Inc.; a 39% equity investment in Wataynikaneyap Power Limited Partnership; and an approximate 60% controlling interest in Caribbean Utilities Company, Ltd. ("Caribbean Utilities"). Also included FortisTCI Limited and Turks and Caicos Utilities Limited (collectively, "FortisTCI") until the September 2, 2025 date of disposition and the 33% equity investment in Belize Electricity Limited ("Belize Electricity") until the October 31, 2025 date of disposition (Note 10). Non-Regulated Corporate and Other: Captures expenses and revenues not specifically related to any reportable segment and those business operations that are below the required threshold for segmented reporting. Consists of non-regulated holding company expenses, and included non-regulated long-term contracted generation assets in Belize until the October 31, 2025 date of disposition (Note 10).

Description of Business

6 Months Ended

Jun. 30, 2026

Organization, Consolidation and Presentation of Financial Statements [Abstract]

DESCRIPTION OF BUSINESS

Nature of Operations

Fortis Inc. ("Fortis" or the "Corporation") is a diversified North American regulated electric and gas utility holding company.

Earnings for interim periods may not be indicative of annual results due to: (i) the impact of seasonal weather conditions on customer demand; (ii) the impact of market conditions, particularly with respect to long-term wholesale sales at UNS Energy; (iii) the timing and significance of any regulatory decisions; and (iv) changes in the U.S. dollar-to-Canadian dollar exchange rate. Earnings for the utilities in Canada and New York tend to be highest in the first and fourth quarters due to space-heating requirements. Earnings for UNS Energy tend to be highest in the second and third quarters due to the use of air conditioning and other cooling equipment.

Entities within the reporting segments that follow operate with substantial autonomy.

Regulated Utilities

ITC: ITC Investment Holdings Inc., ITC Holdings Corp. and the electric transmission operations of its regulated operating subsidiaries, which include International Transmission Company, Michigan Electric Transmission Company, LLC, ITC Midwest LLC and ITC Great Plains, LLC. Fortis owns 80.1% of ITC and an affiliate of GIC Private Limited owns a 19.9% minority interest.

UNS Energy: UNS Energy Corporation, which primarily includes Tucson Electric Power Company ("TEP"), UNS Electric, Inc. ("UNS Electric") and UNS Gas, Inc. ("UNS Gas").

Central Hudson: CH Energy Group, Inc., which primarily includes Central Hudson Gas & Electric Corporation.

FortisBC Energy: FortisBC Energy Inc.

FortisAlberta: FortisAlberta Inc.

FortisBC Electric: FortisBC Inc.

Other Electric: Eastern Canadian and Caribbean utilities, as follows: Newfoundland Power Inc.; Maritime Electric Company, Limited; FortisOntario Inc.; a 39% equity investment in Wataynikaneyap Power Limited Partnership; and an approximate 60% controlling interest in Caribbean Utilities Company, Ltd. ("Caribbean Utilities"). Also included FortisTCI Limited and Turks and Caicos Utilities Limited (collectively, "FortisTCI") until the September 2, 2025 date of disposition and the 33% equity investment in Belize Electricity Limited ("Belize Electricity") until the October 31, 2025 date of disposition (Note 10).

Non-Regulated

Corporate and Other: Captures expenses and revenues not specifically related to any reportable segment and those business operations that are below the required threshold for segmented reporting. Consists of non-regulated holding company expenses, and included non-regulated long-term contracted generation assets in Belize until the October 31, 2025 date of disposition (Note 10).