XML 157 R110.htm IDEA: XBRL DOCUMENT v3.6.0.2
Retirement Benefits (Schedule Of Expected Benefit Payments) (Details)
$ in Millions
Dec. 31, 2016
USD ($)
DB Pension Plan [Member]  
Defined Benefit Plan Disclosure [Line Items]  
Benefit Payments, 2017 $ 153
Benefit Payments, 2018 159
Benefit Payments, 2019 163
Benefit Payments, 2020 165
Benefit Payments, 2021 166
Benefit Payments, 2022-2026 827
DB Pension Plan [Member] | Consumers Energy Company [Member]  
Defined Benefit Plan Disclosure [Line Items]  
Benefit Payments, 2017 149
Benefit Payments, 2018 155
Benefit Payments, 2019 159
Benefit Payments, 2020 161
Benefit Payments, 2021 161
Benefit Payments, 2022-2026 803
DB SERP [Member]  
Defined Benefit Plan Disclosure [Line Items]  
Benefit Payments, 2017 8
Benefit Payments, 2018 8
Benefit Payments, 2019 9
Benefit Payments, 2020 11
Benefit Payments, 2021 10
Benefit Payments, 2022-2026 50
DB SERP [Member] | Consumers Energy Company [Member]  
Defined Benefit Plan Disclosure [Line Items]  
Benefit Payments, 2017 5
Benefit Payments, 2018 5
Benefit Payments, 2019 6
Benefit Payments, 2020 7
Benefit Payments, 2021 7
Benefit Payments, 2022-2026 32
OPEB [Member]  
Defined Benefit Plan Disclosure [Line Items]  
Benefit Payments, 2017 59
Benefit Payments, 2018 63
Benefit Payments, 2019 66
Benefit Payments, 2020 69
Benefit Payments, 2021 72
Benefit Payments, 2022-2026 385
OPEB [Member] | Consumers Energy Company [Member]  
Defined Benefit Plan Disclosure [Line Items]  
Benefit Payments, 2017 57
Benefit Payments, 2018 61
Benefit Payments, 2019 64
Benefit Payments, 2020 67
Benefit Payments, 2021 70
Benefit Payments, 2022-2026 $ 371