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SHORT-TERM DEBT AND LINES OF CREDIT - REVOLVING CREDIT FACILITIES (Details) - USD ($) $ in Millions	Jun. 30, 2026	Dec. 31, 2025
Revolving credit facilities
Short-term credit capacity	$ 3,900.0
Available capacity under existing credit facility	1,968.4
Letter of credit
Revolving credit facilities
Letters of credit issued inside credit facilities	2.3
Commercial paper
Revolving credit facilities
Commercial paper outstanding	1,929.3	$ 1,921.3
WE \| Credit facility maturing August 2030
Revolving credit facilities
Short-term credit capacity	800.0
PGL \| Credit facility maturing August 2030
Revolving credit facilities
Short-term credit capacity	600.0
WPS \| Credit facility maturing August 2030
Revolving credit facilities
Short-term credit capacity	450.0
WG \| Credit facility maturing August 2030
Revolving credit facilities
Short-term credit capacity	350.0
WEC Energy Group \| Credit facility maturing August 2030
Revolving credit facilities
Short-term credit capacity	$ 1,700.0