Retirement Benefits (Tables)

9 Months Ended

Sep. 30, 2024

Defined Benefit Plan Disclosure [Line Items]

Schedule of Net Benefit Costs

Presented in the following table are the costs (credits) and other changes in plan assets and benefit obligations incurred in CMS Energy’s and Consumers’ retirement benefit plans:

In Millions
	DB Pension Plans												OPEB Plan
	Three Months Ended						Nine Months Ended						Three Months Ended						Nine Months Ended
September 30	2024			2023			2024			2023			2024			2023			2024			2023
CMS Energy, including Consumers
Net periodic credit
Service cost		$	7		$	7		$	21		$	22		$	2		$	2		$	8		$	8
Interest cost		26			27			78			80			10			11			32			33
Expected return on plan assets		(58)			(55)			(176)			(165)			(28)			(26)			(86)			(77)
Amortization of:
Net loss		3			2			9			8			1			3			3			9
Prior service cost (credit)		1			1			3			3			(7)			(10)			(23)			(31)
Settlement loss		3			3			8			8			—			—			—			—
Net periodic credit		$	(18)		$	(15)		$	(57)		$	(44)		$	(22)		$	(20)		$	(66)		$	(58)
Consumers
Net periodic credit
Service cost		$	7		$	7		$	20		$	21		$	2		$	2		$	8		$	8
Interest cost		25			24			74			75			11			10			31			31
Expected return on plan assets		(56)			(52)			(166)			(156)			(26)			(23)			(80)			(71)
Amortization of:
Net loss		3			3			8			8			1			3			3			9
Prior service cost (credit)		1			1			3			3			(8)			(10)			(23)			(30)
Settlement loss		3			3			8			8			—			—			—			—
Net periodic credit		$	(17)		$	(14)		$	(53)		$	(41)		$	(20)		$	(18)		$	(61)		$	(53)

Consumers Energy Company

Defined Benefit Plan Disclosure [Line Items]

Schedule of Net Benefit Costs

Presented in the following table are the costs (credits) and other changes in plan assets and benefit obligations incurred in CMS Energy’s and Consumers’ retirement benefit plans:

In Millions
	DB Pension Plans												OPEB Plan
	Three Months Ended						Nine Months Ended						Three Months Ended						Nine Months Ended
September 30	2024			2023			2024			2023			2024			2023			2024			2023
CMS Energy, including Consumers
Net periodic credit
Service cost		$	7		$	7		$	21		$	22		$	2		$	2		$	8		$	8
Interest cost		26			27			78			80			10			11			32			33
Expected return on plan assets		(58)			(55)			(176)			(165)			(28)			(26)			(86)			(77)
Amortization of:
Net loss		3			2			9			8			1			3			3			9
Prior service cost (credit)		1			1			3			3			(7)			(10)			(23)			(31)
Settlement loss		3			3			8			8			—			—			—			—
Net periodic credit		$	(18)		$	(15)		$	(57)		$	(44)		$	(22)		$	(20)		$	(66)		$	(58)
Consumers
Net periodic credit
Service cost		$	7		$	7		$	20		$	21		$	2		$	2		$	8		$	8
Interest cost		25			24			74			75			11			10			31			31
Expected return on plan assets		(56)			(52)			(166)			(156)			(26)			(23)			(80)			(71)
Amortization of:
Net loss		3			3			8			8			1			3			3			9
Prior service cost (credit)		1			1			3			3			(8)			(10)			(23)			(30)
Settlement loss		3			3			8			8			—			—			—			—
Net periodic credit		$	(17)		$	(14)		$	(53)		$	(41)		$	(20)		$	(18)		$	(61)		$	(53)