Retirement Benefits (Tables)

9 Months Ended

Sep. 30, 2015

Defined Benefit Plan Disclosure [Line Items]

Schedule Of Net Benefit Costs

In Millions
	DB Pension Plan												OPEB Plan
	Three Months Ended						Nine Months Ended						Three Months Ended						Nine Months Ended
September 30	2015			2014			2015			2014			2015			2014			2015			2014
CMS Energy, including Consumers
Net periodic cost (credit)
Service cost		$	13		$	10		$	37		$	30		$	7		$	5		$	19		$	15
Interest expense			26			24			77			74			14			14			43			42
Expected return on plan assets			(35)			(33)			(104)			(101)			(23)			(22)			(68)			(66)
Amortization of:
Net loss			22			14			67			43			5			1			16			2
Prior service cost (credit)			-			-			1			1			(10)			(10)			(31)			(31)
Net periodic cost (credit)		$	26		$	15		$	78		$	47		$	(7)		$	(12)		$	(21)		$	(38)
Consumers
Net periodic cost (credit)
Service cost		$	12		$	10		$	36		$	30		$	7		$	5		$	19		$	15
Interest expense			25			24			74			72			14			13			42			40
Expected return on plan assets			(34)			(33)			(101)			(99)			(22)			(20)			(65)			(62)
Amortization of:
Net loss			22			14			66			42			6			-			17			2
Prior service cost (credit)			-			-			1			1			(10)			(10)			(30)			(30)
Net periodic cost (credit)		$	25		$	15		$	76		$	46		$	(5)		$	(12)		$	(17)		$	(35)

Consumers Energy Company [Member]

Defined Benefit Plan Disclosure [Line Items]

Schedule Of Net Benefit Costs

In Millions
	DB Pension Plan												OPEB Plan
	Three Months Ended						Nine Months Ended						Three Months Ended						Nine Months Ended
September 30	2015			2014			2015			2014			2015			2014			2015			2014
CMS Energy, including Consumers
Net periodic cost (credit)
Service cost		$	13		$	10		$	37		$	30		$	7		$	5		$	19		$	15
Interest expense			26			24			77			74			14			14			43			42
Expected return on plan assets			(35)			(33)			(104)			(101)			(23)			(22)			(68)			(66)
Amortization of:
Net loss			22			14			67			43			5			1			16			2
Prior service cost (credit)			-			-			1			1			(10)			(10)			(31)			(31)
Net periodic cost (credit)		$	26		$	15		$	78		$	47		$	(7)		$	(12)		$	(21)		$	(38)
Consumers
Net periodic cost (credit)
Service cost		$	12		$	10		$	36		$	30		$	7		$	5		$	19		$	15
Interest expense			25			24			74			72			14			13			42			40
Expected return on plan assets			(34)			(33)			(101)			(99)			(22)			(20)			(65)			(62)
Amortization of:
Net loss			22			14			66			42			6			-			17			2
Prior service cost (credit)			-			-			1			1			(10)			(10)			(30)			(30)
Net periodic cost (credit)		$	25		$	15		$	76		$	46		$	(5)		$	(12)		$	(17)		$	(35)