Consolidated Statements Of Cash Flows (USD $) In Millions, unless otherwise specified	6 Months Ended
Jun. 30, 2013	Jun. 30, 2012
Cash Flows from Operating Activities
Net income	$ 225	$ 168
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	318	302
Deferred income taxes and investment tax credit	135	102
Postretirement benefits expense	95	94
Other non-cash operating activities	32	35
Postretirement benefits contributions	(88)	(37)
Proceeds from government grant	69
Cash provided by (used in) changes in assets and liabilities
Decrease (increase) in accounts receivable, notes receivable, and accrued revenue	85	146
Decrease (increase) in inventories	253	135
Increase (decrease) in accounts payable	19	10
Increase (decrease) in accrued expenses	(82)	(82)
Other current and non-current assets and liabilities	34	70
Net cash provided by operating activities	1,095	943
Cash Flows from Investing Activities
Capital expenditures (excludes assets placed under capital lease)	(580)	(575)
Cost to retire property	(23)	(20)
Other investing activities	(13)	(15)
Net cash used in investing activities	(616)	(610)
Cash Flows from Financing Activities
Proceeds from issuance of long-term debt	675	790
Proceeds from (retirements of) EnerBank notes, net	(28)	(4)
Issuance of common stock	28	23
Retirement of long-term debt	(445)	(972)
Payment of common stock dividends	(135)	(125)
Increase (decrease) in notes payable	(110)
Payment of capital lease obligations and other financing costs	(20)	(19)
Net cash provided by (used in) financing activities	(35)	(307)
Net Increase in Cash and Cash Equivalents	444	26
Cash and Cash Equivalents, Beginning of Period	93	161
Cash and Cash Equivalents, End of Period	537	187
Consumers Energy Company [Member]
Cash Flows from Operating Activities
Net income	262	198
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	316	299
Deferred income taxes and investment tax credit	87	39
Postretirement benefits expense	93	92
Other non-cash operating activities	31	31
Postretirement benefits contributions	(86)	(34)
Proceeds from government grant	69
Cash provided by (used in) changes in assets and liabilities
Decrease (increase) in accounts receivable, notes receivable, and accrued revenue	85	146
Decrease (increase) in inventories	249	137
Increase (decrease) in accounts payable	23	11
Increase (decrease) in accrued expenses	(73)	(19)
Other current and non-current assets and liabilities	29	113
Net cash provided by operating activities	1,085	1,013
Cash Flows from Investing Activities
Capital expenditures (excludes assets placed under capital lease)	(579)	(572)
Cost to retire property	(23)	(20)
Other investing activities	(11)	(9)
Net cash used in investing activities	(613)	(601)
Cash Flows from Financing Activities
Proceeds from issuance of long-term debt	425	375
Retirement of long-term debt	(445)	(694)
Payment of common stock dividends	(195)	(159)
Stockholder contribution	150	150
Increase (decrease) in notes payable	(110)
Payment of capital lease obligations and other financing costs	(16)	(15)
Net cash provided by (used in) financing activities	(191)	(343)
Net Increase in Cash and Cash Equivalents	281	69
Cash and Cash Equivalents, Beginning of Period	5	85
Cash and Cash Equivalents, End of Period	$ 286	$ 154

Cash grant received from government during the current period.

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- Definition

The cash outflow for the obligation for a lease meeting the criteria for capitalization (with maturities exceeding on year or beyond the operating cycle of the entity, if longer) and other financing costs.

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No definition available.

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The aggregate amount of adjustments to net income or loss necessary to remove the effects of all items whose cash effects are investing or financing cash flows. The aggregate amount also includes all noncash expenses and income items which reduce or increase net income and are thus added back or deducted when calculating cash provided by or used in operating activities.

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Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

+ References

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Amount of increase (decrease) in cash and cash equivalents. Cash and cash equivalents are the amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Includes effect from exchange rate changes.

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Amount of deferred income tax expense (benefit) and income tax credits.

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- Definition

The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets.

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- Definition

The increase (decrease) during the reporting period in the amount due from customers for the credit sale of goods and services; includes accounts receivable and other types of receivables.

+ References