Regulatory Matters	6 Months Ended
Regulatory Matters	Jun. 30, 2018
Public Utilities, General Disclosures [Line Items]
Regulatory Matters	Regulatory Matters Regulatory matters are critical to Consumers. The Michigan Attorney General, ABATE, the MPSC Staff, and certain other parties typically participate in MPSC proceedings concerning Consumers, such as Consumers’ rate cases and PSCR and GCR processes. These parties often challenge various aspects of those proceedings, including the prudence of Consumers’ policies and practices, and seek cost disallowances and other relief. The parties also have appealed significant MPSC orders. Depending upon the specific issues, the outcomes of rate cases and proceedings, including judicial proceedings challenging MPSC orders or other actions, could negatively affect CMS Energy’s and Consumers’ liquidity, financial condition, and results of operations. Consumers cannot predict the outcome of these proceedings. There are multiple appeals pending that involve various issues concerning cost recovery from customers, the adequacy of the record evidence supporting the recovery of Smart Energy investments, and other matters. Consumers is unable to predict the outcome of these appeals. Electric Rate Case: In March 2017, Consumers filed an application with the MPSC seeking an annual rate increase of $173 million, based on a 10.5 percent authorized return on equity. The filing requested authority to recover new investment in system reliability, environmental compliance, and technology enhancements. In September 2017, Consumers reduced its requested annual rate increase to $148 million. In October 2017, Consumers self-implemented an annual rate increase of $130 million, subject to refund with interest and potential penalties. The MPSC issued an order in March 2018, authorizing an annual rate increase of $66 million, based on a 10.0 percent authorized return on equity. In June 2018, as a result of a petition for rehearing filed by Consumers, the MPSC issued an order adjusting the authorized annual rate increase to $72 million by allowing recovery of additional retirement benefit plan costs. Consumers had a recorded liability of $35 million for customer refunds at June 30, 2018. Gas Rate Case: In February 2018, the MPSC Staff filed testimony in the general gas rate case that Consumers filed in October 2017. In its testimony, the MPSC Staff recommended the disallowance of cost recovery for certain categories of historical capital expenditures incurred by Consumers, totaling over $115 million. In July 2018, the administrative law judge issued a proposal for decision supporting a portion of the MPSC Staff’s recommended disallowance, totaling $100 million. If the MPSC were to adopt some or all of the administrative law judge’s recommendations, Consumers would be required to write off up to $145 million of assets; this range of loss takes into account Consumers’ actual historical costs. A material disallowance of historical costs could negatively affect CMS Energy’s and Consumers’ results of operations. While Consumers cannot predict the outcome of this proceeding, it does not believe it is probable that the MPSC will disallow these historical capital expenditures in the final order, as there is no regulatory precedent of a disallowance of this type. Tax Cuts and Jobs Act: The TCJA, which changed existing federal tax law and included numerous provisions that affect businesses, was signed into law in December 2017. In February 2018, the MPSC ordered Consumers to file various proceedings to determine the reduction in its electric and gas revenue requirements as a result of the TCJA. The MPSC also ordered Consumers to implement bill credits to reflect that reduction until customer rates are adjusted through Consumers’ general rate cases. Consumers filed the first of these proceedings in March 2018, requesting a $49 million reduction in its annual gas revenue requirement. The MPSC approved this reduction in June 2018, with credits to customer bills beginning in July 2018. Consumers filed the second proceeding in April 2018, requesting a $113 million reduction in its annual electric revenue requirement. The MPSC approved this reduction in July 2018, with credits to customer bills beginning in August 2018. These credits will reduce rates prospectively for the impact of the TCJA but do not include potential refunds associated with Consumers’ remeasurement of its deferred income taxes; these will be considered in a subsequent proceeding. By October 2018, Consumers will file two more proceedings to address amounts collected from customers during 2018 through the implementation of the first two proceedings. Consumers’ liability for customer refunds for amounts over-collected during that time was $88 million at June 30, 2018. Consumers will also file, by October 2018, additional proceedings to address the December 31, 2017 remeasurement of its deferred income taxes and any other impacts of the TCJA on customers. For additional details on the remeasurement, see Note 9, Income Taxes. Energy Waste Reduction Plan Incentive: Consumers filed its 2017 energy waste reduction reconciliation in May 2018, requesting the MPSC’s approval to collect from customers the maximum performance incentive of $31 million for exceeding its statutory savings targets in 2017. Consumers recognized incentive revenue under this program of $31 million in 2017.
Consumers Energy Company
Public Utilities, General Disclosures [Line Items]
Regulatory Matters	Regulatory Matters Regulatory matters are critical to Consumers. The Michigan Attorney General, ABATE, the MPSC Staff, and certain other parties typically participate in MPSC proceedings concerning Consumers, such as Consumers’ rate cases and PSCR and GCR processes. These parties often challenge various aspects of those proceedings, including the prudence of Consumers’ policies and practices, and seek cost disallowances and other relief. The parties also have appealed significant MPSC orders. Depending upon the specific issues, the outcomes of rate cases and proceedings, including judicial proceedings challenging MPSC orders or other actions, could negatively affect CMS Energy’s and Consumers’ liquidity, financial condition, and results of operations. Consumers cannot predict the outcome of these proceedings. There are multiple appeals pending that involve various issues concerning cost recovery from customers, the adequacy of the record evidence supporting the recovery of Smart Energy investments, and other matters. Consumers is unable to predict the outcome of these appeals. Electric Rate Case: In March 2017, Consumers filed an application with the MPSC seeking an annual rate increase of $173 million, based on a 10.5 percent authorized return on equity. The filing requested authority to recover new investment in system reliability, environmental compliance, and technology enhancements. In September 2017, Consumers reduced its requested annual rate increase to $148 million. In October 2017, Consumers self-implemented an annual rate increase of $130 million, subject to refund with interest and potential penalties. The MPSC issued an order in March 2018, authorizing an annual rate increase of $66 million, based on a 10.0 percent authorized return on equity. In June 2018, as a result of a petition for rehearing filed by Consumers, the MPSC issued an order adjusting the authorized annual rate increase to $72 million by allowing recovery of additional retirement benefit plan costs. Consumers had a recorded liability of $35 million for customer refunds at June 30, 2018. Gas Rate Case: In February 2018, the MPSC Staff filed testimony in the general gas rate case that Consumers filed in October 2017. In its testimony, the MPSC Staff recommended the disallowance of cost recovery for certain categories of historical capital expenditures incurred by Consumers, totaling over $115 million. In July 2018, the administrative law judge issued a proposal for decision supporting a portion of the MPSC Staff’s recommended disallowance, totaling $100 million. If the MPSC were to adopt some or all of the administrative law judge’s recommendations, Consumers would be required to write off up to $145 million of assets; this range of loss takes into account Consumers’ actual historical costs. A material disallowance of historical costs could negatively affect CMS Energy’s and Consumers’ results of operations. While Consumers cannot predict the outcome of this proceeding, it does not believe it is probable that the MPSC will disallow these historical capital expenditures in the final order, as there is no regulatory precedent of a disallowance of this type. Tax Cuts and Jobs Act: The TCJA, which changed existing federal tax law and included numerous provisions that affect businesses, was signed into law in December 2017. In February 2018, the MPSC ordered Consumers to file various proceedings to determine the reduction in its electric and gas revenue requirements as a result of the TCJA. The MPSC also ordered Consumers to implement bill credits to reflect that reduction until customer rates are adjusted through Consumers’ general rate cases. Consumers filed the first of these proceedings in March 2018, requesting a $49 million reduction in its annual gas revenue requirement. The MPSC approved this reduction in June 2018, with credits to customer bills beginning in July 2018. Consumers filed the second proceeding in April 2018, requesting a $113 million reduction in its annual electric revenue requirement. The MPSC approved this reduction in July 2018, with credits to customer bills beginning in August 2018. These credits will reduce rates prospectively for the impact of the TCJA but do not include potential refunds associated with Consumers’ remeasurement of its deferred income taxes; these will be considered in a subsequent proceeding. By October 2018, Consumers will file two more proceedings to address amounts collected from customers during 2018 through the implementation of the first two proceedings. Consumers’ liability for customer refunds for amounts over-collected during that time was $88 million at June 30, 2018. Consumers will also file, by October 2018, additional proceedings to address the December 31, 2017 remeasurement of its deferred income taxes and any other impacts of the TCJA on customers. For additional details on the remeasurement, see Note 9, Income Taxes. Energy Waste Reduction Plan Incentive: Consumers filed its 2017 energy waste reduction reconciliation in May 2018, requesting the MPSC’s approval to collect from customers the maximum performance incentive of $31 million for exceeding its statutory savings targets in 2017. Consumers recognized incentive revenue under this program of $31 million in 2017.