LONG-TERM DEBT (Details)		1 Months Ended		3 Months Ended		6 Months Ended
	Feb. 07, 2024 USD ($)	May 31, 2024 USD ($)	Mar. 31, 2024 USD ($)	Jun. 30, 2024 USD ($) d $ / shares	Jun. 30, 2023 USD ($)	Jun. 30, 2024 USD ($) $ / shares shares	Jun. 30, 2023 USD ($)
Debt Instrument [Line Items]
Interest expense				$ 200,600,000	$ 178,700,000	$ 392,600,000	$ 350,900,000
5.00% WE Debentures due 05/15/2029 | WE
Debt Instrument [Line Items]
Interest rate on long-term debt		5.00%
Proceeds from issuance of debt		$ 350,000,000.0
WEC Energy Group | Floating Rate WEC Energy Group Junior Notes Due 2067
Debt Instrument [Line Items]
Extinguishment of debt	$ 122,100,000	19,000,000.0
Unsecured debt	500,000,000	377,900,000
Repayment of long-term debt	115,200,000	$ 18,700,000
Gain on early extinguishment of debt	$ 6,900,000
WEC Energy Group | WEC 0.80% Senior Notes $600M due March 15, 2024
Debt Instrument [Line Items]
Repayment of long-term debt			$ 600,000,000.0
Interest rate on long-term debt			0.80%
WEC Energy Group | WEC 4.375% Convertible Notes due June 1, 2027
Debt Instrument [Line Items]
Interest rate on long-term debt				4.375%		4.375%
Proceeds from issuance of debt				$ 862,500,000
Initial conversion ratio				10.1243
Principal amount conversion rate applied to				$ 1,000		$ 1,000
Initial conversion price, per share | $ / shares				$ 98.77		$ 98.77
Senior Notes				$ 862,500,000		$ 862,500,000
Unamortized debt issuance costs				(9,000,000.0)		(9,000,000.0)
Net carrying amount				853,500,000		853,500,000
Fair value amount				856,400,000		856,400,000
Contractual interest expense				3,500,000		3,500,000
Amortization of debt issuance costs				300,000		300,000
Interest expense				$ 3,800,000		$ 3,800,000
Number of shares outstanding related to the potential conversion of the Notes included in diluted eps | shares						0
WEC Energy Group | WEC 4.375% Convertible Notes due June 1, 2027 | Early redemption terms
Debt Instrument [Line Items]
Debt instrument, redemption price, percentage				100.00%
WEC Energy Group | WEC 4.375% Convertible Notes due June 1, 2027 | Debt conversion terms one
Debt Instrument [Line Items]
Threshold percentage of trigger				130.00%
Trading days | d				20
Consecutive trading days | d				30
WEC Energy Group | WEC 4.375% Convertible Notes due June 1, 2027 | Debt conversion terms two
Debt Instrument [Line Items]
Threshold percentage of trigger				98.00%
Trading days | d				5
Consecutive trading days | d				10
Principal amount conversion rate applied to				$ 1,000		$ 1,000
WEC Energy Group | WEC 4.375% Convertible Notes due June 1, 2027 | Debt conversion terms four
Debt Instrument [Line Items]
Trading days prior to maturity | d				2
WEC Energy Group | WEC 4.375% Convertible Notes due June 1, 2029
Debt Instrument [Line Items]
Interest rate on long-term debt				4.375%		4.375%
Proceeds from issuance of debt				$ 862,500,000
Initial conversion ratio				10.1243
Principal amount conversion rate applied to				$ 1,000		$ 1,000
Initial conversion price, per share | $ / shares				$ 98.77		$ 98.77
Senior Notes				$ 862,500,000		$ 862,500,000
Unamortized debt issuance costs				(9,200,000)		(9,200,000)
Net carrying amount				853,300,000		853,300,000
Fair value amount				856,500,000		856,500,000
Contractual interest expense				3,500,000		3,500,000
Amortization of debt issuance costs				200,000		200,000
Interest expense				$ 3,700,000		$ 3,700,000
Number of shares outstanding related to the potential conversion of the Notes included in diluted eps | shares						0
WEC Energy Group | WEC 4.375% Convertible Notes due June 1, 2029 | Early redemption terms
Debt Instrument [Line Items]
Trading days prior to early redemption | d				41
Threshold percentage of trigger				130.00%
Trading days | d				20
Consecutive trading days | d				30
Debt instrument, redemption price, percentage				100.00%
WEC Energy Group | WEC 4.375% Convertible Notes due June 1, 2029 | Debt conversion terms one
Debt Instrument [Line Items]
Threshold percentage of trigger				130.00%
Trading days | d				20
Consecutive trading days | d				30
WEC Energy Group | WEC 4.375% Convertible Notes due June 1, 2029 | Debt conversion terms two
Debt Instrument [Line Items]
Threshold percentage of trigger				98.00%
Trading days | d				5
Consecutive trading days | d				10
Principal amount conversion rate applied to				$ 1,000		$ 1,000
WEC Energy Group | WEC 4.375% Convertible Notes due June 1, 2029 | Debt conversion terms three
Debt Instrument [Line Items]
Trading days prior to redemption | d				2
WEC Energy Group | WEC 4.375% Convertible Notes due June 1, 2029 | Debt conversion terms four
Debt Instrument [Line Items]
Trading days prior to maturity | d				2