COMMITMENTS, GUARANTEES AND CONTINGENCIES - Narrative (Details)	3 Months Ended
	Jun. 30, 2024 USD ($)	Apr. 30, 2025 USD ($)	Mar. 31, 2025 USD ($) unit uncommittedFacility
Other Commitments [Line Items]
Number of uncommitted facilities | uncommittedFacility			6
CCR Rule Revision
Other Commitments [Line Items]
Asset retirement obligation, liabilities incurred	$ 674,000,000
I&M | Cook plant
Other Commitments [Line Items]
Nuclear contingencies, number of units | unit			2
Line of Credit | Revolving Credit Facility | Revolving Credit Facility, Due March 2029
Other Commitments [Line Items]
Line of credit facility, borrowing capacity			$ 5,000,000,000
Line of Credit | Revolving Credit Facility | Revolving Credit Facility, Due March 2027
Other Commitments [Line Items]
Line of credit facility, borrowing capacity			1,000,000,000
Line of Credit | Letter of Credit
Other Commitments [Line Items]
Debt instrument, face amount			450,000,000
Line of Credit | Letter of Credit | Subsequent Event
Other Commitments [Line Items]
Debt instrument, face amount		$ 52,000,000
Line of Credit | Letter of Credit | Subsidiaries
Other Commitments [Line Items]
Line of credit facility, borrowing capacity			1,200,000,000
Line of Credit | Letter of Credit | Revolving Credit Facility, Due March 2029
Other Commitments [Line Items]
Line of credit facility, borrowing capacity			0
Line of Credit | Letter of Credit | Revolving Credit Facility, Due March 2027
Other Commitments [Line Items]
Line of credit facility, borrowing capacity			$ 0