Schedule I - Long-Term Debt (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Future maturities of long-term debt outstanding
2018	$ 838.4
2020	686.9
Thereafter	7,336.0
Total	9,600.9
Long-term notes outstanding	8,746.6	$ 9,158.2
WEC Energy Group
Future maturities of long-term debt outstanding
2018	300.0
2020	400.0
Thereafter	1,200.0
Total	1,900.0
Long-term notes outstanding	1,592.3	$ 1,890.0
WEC Energy Group \| WECC \| Support Agreement Related to WECC Debt
Future maturities of long-term debt outstanding
Long-term notes outstanding	$ 50.0

Face (par) amount of debt instrument at time of issuance.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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