XML 173 R98.htm IDEA: XBRL DOCUMENT
v3.6.0.2

Long-Term Debt and Capital Lease Obligations - Long-term Debt (Details) - USD ($) $ in Millions | 1 Months Ended | 12 Months Ended |  |  |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Dec. 31, 2016 | Nov. 30, 2016 | Sep. 30, 2016 | Jun. 30, 2016 | Feb. 29, 2016 | Dec. 31, 2016 | Nov. 01, 2016 | Oct. 01, 2016 | Sep. 01, 2016 | Aug. 01, 2016 | Jun. 01, 2016 | Feb. 01, 2016 | Dec. 31, 2015
Debt Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Long-term Pollution Control Bond | $ 80.0 |  |  |  |  | $ 80.0 |  |  |  | $ 67.0 |  |  |
Common Stock, Value, Issued | 3.2 |  |  |  |  | 3.2 |  |  |  |  |  |  | $ 3.2
Future maturities of our long-term debt outstanding |  |  |  |  |  |  |  |  |  |  |  |  |
2017 | 154.5 |  |  |  |  | 154.5 |  |  |  |  |  |  |
2018 | 836.1 |  |  |  |  | 836.1 |  |  |  |  |  |  |
2019 | 357.7 |  |  |  |  | 357.7 |  |  |  |  |  |  |
2020 | 684.4 |  |  |  |  | 684.4 |  |  |  |  |  |  |
2021 | 336.2 |  |  |  |  | 336.2 |  |  |  |  |  |  |
Thereafter | 6,953.5 |  |  |  |  | 6,953.5 |  |  |  |  |  |  |
Total | $ 9,322.4 |  |  |  |  | $ 9,322.4 |  |  |  |  |  |  |
PGL Fixed First and Refunding Mortgage XX Series 2.21 Percent Bonds, Due 2016 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument interest rate stated percentage rate | 2.21% |  |  |  |  | 2.21% |  |  |  |  |  |  |
PGL Fixed First and Refunding Mortgage RR Series 4.3 Percent Bonds, Due 2035 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument interest rate stated percentage rate | 4.30% |  |  |  |  | 4.30% |  |  |  |  |  |  |
We Power Notes (secured, nonrecourse), 4.91% due 2015-2030 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument interest rate stated percentage rate | 4.91% |  |  |  |  | 4.91% |  |  |  |  |  |  |
We Power Notes (secured, nonrecourse), 6.00% due 2015-2033 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument interest rate stated percentage rate | 6.00% |  |  |  |  | 6.00% |  |  |  |  |  |  |
We Power Notes (secured, nonrecourse), 5.209% due 2015-2030 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument interest rate stated percentage rate | 5.209% |  |  |  |  | 5.209% |  |  |  |  |  |  |
We Power Notes (secured, nonrecourse), 4.673% due 2015-2031 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument interest rate stated percentage rate | 4.673% |  |  |  |  | 4.673% |  |  |  |  |  |  |
TEG Unsecured Senior Notes 8 Percent, Due 2016 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument interest rate stated percentage rate | 8.00% |  |  |  |  | 8.00% |  |  |  |  |  |  |
TEG Junior Subordinated Notes, 6.11% due 2066 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument interest rate stated percentage rate | 3.05% |  |  |  |  | 3.05% |  |  |  |  |  |  | 6.11%
Debt Instrument, Basis Spread on Variable Rate |  |  |  |  |  | 2.12% |  |  |  |  |  |  |
TEG Unsecured Senior Notes 4.17 Percent, Due 2020 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument interest rate stated percentage rate | 4.17% |  |  |  |  | 4.17% |  |  |  |  |  |  |
WEC Notes (unsecured), 6.20% due 2033 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument interest rate stated percentage rate | 6.20% |  |  |  |  | 6.20% |  |  |  |  |  |  |
WEC Junior Notes (unsecured), 6.25% due 2067 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument interest rate stated percentage rate | 6.25% |  |  |  |  | 6.25% |  |  |  |  |  |  |
Debt Instrument, Basis Spread on Variable Rate |  |  |  |  |  | 2.1125% |  |  |  |  |  |  |
TEG Junior Subordinated Notes, 6.00% due 2073 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument interest rate stated percentage rate | 6.00% |  |  |  |  | 6.00% |  |  |  |  |  |  |
WG | WG Debentures, 3.71% due 2046 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument interest rate stated percentage rate |  |  |  |  |  |  |  |  | 3.71% |  |  |  |
Proceeds from Issuance of Debt |  |  | $ 200.0 |  |  |  |  |  |  |  |  |  |
PGL | PGL 3.65% Series DDD Bonds due 2046 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument interest rate stated percentage rate |  |  |  |  |  |  |  | 3.65% |  |  |  |  |
Proceeds from Issuance of Debt | $ 150.0 |  |  |  |  |  |  |  |  |  |  |  |
PGL | PGL 3.65% Series CCC Bonds due 2046 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument interest rate stated percentage rate |  |  |  |  |  |  | 3.65% |  |  |  |  |  |
Proceeds from Issuance of Debt |  | $ 50.0 |  |  |  |  |  |  |  |  |  |  |
PGL | PGL Fixed First and Refunding Mortgage XX Series 2.21 Percent Bonds, Due 2016 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument interest rate stated percentage rate |  |  |  |  |  |  | 2.21% |  |  |  |  |  |
Extinguishment of Debt, Amount |  | $ 50.0 |  |  |  |  |  |  |  |  |  |  |
PGL | PGL Fixed First and Refunding Mortgage RR Series 4.3 Percent Bonds, Due 2035 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument interest rate stated percentage rate |  |  |  |  |  |  |  |  |  |  | 4.30% |  |
Extinguishment of Debt, Amount |  |  |  | $ 50.0 |  |  |  |  |  |  |  |  |
We Power | We Power Notes (secured, nonrecourse), 4.91% due 2015-2030 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument interest rate stated percentage rate | 4.91% |  |  |  |  | 4.91% |  |  |  |  |  |  |
Long-term Debt, Gross | $ 106.7 |  |  |  |  | $ 106.7 |  |  |  |  |  |  |
Long-term Debt, Current Maturities | $ 5.6 |  |  |  |  | $ 5.6 |  |  |  |  |  |  |
We Power | We Power Notes (secured, nonrecourse), 6.00% due 2015-2033 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument interest rate stated percentage rate | 6.00% |  |  |  |  | 6.00% |  |  |  |  |  |  |
Long-term Debt, Gross | $ 126.1 |  |  |  |  | $ 126.1 |  |  |  |  |  |  |
Long-term Debt, Current Maturities | $ 4.6 |  |  |  |  | $ 4.6 |  |  |  |  |  |  |
We Power | We Power Notes (secured, nonrecourse), 5.209% due 2015-2030 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument interest rate stated percentage rate | 5.209% |  |  |  |  | 5.209% |  |  |  |  |  |  |
Long-term Debt, Gross | $ 204.8 |  |  |  |  | $ 204.8 |  |  |  |  |  |  |
Long-term Debt, Current Maturities | $ 10.8 |  |  |  |  | $ 10.8 |  |  |  |  |  |  |
We Power | We Power Notes (secured, nonrecourse), 4.673% due 2015-2031 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument interest rate stated percentage rate | 4.673% |  |  |  |  | 4.673% |  |  |  |  |  |  |
Long-term Debt, Gross | $ 170.9 |  |  |  |  | $ 170.9 |  |  |  |  |  |  |
Long-term Debt, Current Maturities | 8.5 |  |  |  |  | 8.5 |  |  |  |  |  |  |
Integrys Holding Inc |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Common Stock, Value, Issued |  |  |  |  |  |  |  |  |  |  |  | $ 66.4 |
Integrys Holding Inc | TEG Unsecured Senior Notes 8 Percent, Due 2016 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument interest rate stated percentage rate |  |  |  |  |  |  |  |  |  |  | 8.00% |  |
Unsecured Long-term Debt, Noncurrent | 0.0 |  |  |  |  | 0.0 |  |  |  |  |  |  | $ 50.0
Extinguishment of Debt, Amount |  |  |  | $ 50.0 |  |  |  |  |  |  |  |  |
Integrys Holding Inc | TEG Junior Subordinated Notes, 6.11% due 2066 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument interest rate stated percentage rate |  |  |  |  |  |  |  |  |  |  |  | 6.11% |
Unsecured Long-term Debt, Noncurrent | 114.9 |  |  |  |  | $ 114.9 |  |  |  |  |  |  | 269.8
Debt Instrument, Basis Spread on Variable Rate |  |  |  |  |  | 2.12% |  |  |  |  |  |  |
Debt Instrument, Repurchase Amount |  |  |  |  |  |  |  |  |  |  |  | $ 128.6 |
Long-term Debt, Gross | 114.9 |  |  |  |  | $ 114.9 |  |  |  |  |  |  |
Extinguishment of Debt, Amount |  |  |  |  | $ 154.9 |  |  |  |  |  |  |  |
Integrys Holding Inc | TEG Unsecured Senior Notes 4.17 Percent, Due 2020 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Unsecured Long-term Debt, Noncurrent | $ 250.0 |  |  |  |  | $ 250.0 |  |  |  |  |  |  | 250.0
Integrys Holding Inc | TEG Junior Subordinated Notes, 6.00% due 2073 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument interest rate stated percentage rate | 6.00% |  |  |  |  | 6.00% |  |  |  |  |  |  |
Unsecured Long-term Debt, Noncurrent | $ 400.0 |  |  |  |  | $ 400.0 |  |  |  |  |  |  | 400.0
Long-term Debt, Gross | 400.0 |  |  |  |  | 400.0 |  |  |  |  |  |  |
WEC Energy Group |  |  |  |  |  |  |  |  |  |  |  |  |
Future maturities of our long-term debt outstanding |  |  |  |  |  |  |  |  |  |  |  |  |
2018 | 300.0 |  |  |  |  | 300.0 |  |  |  |  |  |  |
2020 | 400.0 |  |  |  |  | 400.0 |  |  |  |  |  |  |
Thereafter | 1,200.0 |  |  |  |  | 1,200.0 |  |  |  |  |  |  |
Total | $ 1,900.0 |  |  |  |  | $ 1,900.0 |  |  |  |  |  |  |
WEC Energy Group | WEC Notes (unsecured), 6.20% due 2033 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument interest rate stated percentage rate | 6.20% |  |  |  |  | 6.20% |  |  |  |  |  |  |
Unsecured Long-term Debt, Noncurrent | $ 200.0 |  |  |  |  | $ 200.0 |  |  |  |  |  |  | 200.0
WEC Energy Group | WEC Junior Notes (unsecured), 6.25% due 2067 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument interest rate stated percentage rate | 6.25% |  |  |  |  | 6.25% |  |  |  |  |  |  |
Unsecured Long-term Debt, Noncurrent | $ 500.0 |  |  |  |  | $ 500.0 |  |  |  |  |  |  | $ 500.0

X
- Definition Aggregate par or stated value of issued nonredeemable common stock (or common stock redeemable solely at the option of the issuer). This item includes treasury stock repurchased by the entity. Note: elements for number of nonredeemable common shares, par value and other disclosure concepts are in another section within stockholders' equity. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_CommonStockValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_DebtDisclosureAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage points added to the reference rate to compute the variable rate on the debt instrument. + References No definition available. + Details
Name: | us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(16)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
Name: | us-gaap_DebtInstrumentCarryingAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Face (par) amount of debt instrument at time of issuance. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399 + Details
Name: | us-gaap_DebtInstrumentFaceAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Fair value amount of debt instrument that was repurchased. + References No definition available. + Details
Name: | us-gaap_DebtInstrumentRepurchaseAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Gross amount of debt extinguished. + References No definition available. + Details
Name: | us-gaap_ExtinguishmentOfDebtAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_LongTermDebtByMaturityAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19,20) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_LongTermDebtCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition 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. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6802200&loc=d3e1835-112601 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 3 -Subparagraph (SX 210.12-04.(a)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24072-122690 + Details
Name: | us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition 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 in the next 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. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 3 -Subparagraph (SX 210.12-04.(a)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24072-122690 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6802200&loc=d3e1835-112601 + Details
Name: | us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition 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 in 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. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6802200&loc=d3e1835-112601 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 3 -Subparagraph (SX 210.12-04.(a)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24072-122690 + Details
Name: | us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition 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 in the fourth 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. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 3 -Subparagraph (SX 210.12-04.(a)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24072-122690 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6802200&loc=d3e1835-112601 + Details
Name: | us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition 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 in the third 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. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6802200&loc=d3e1835-112601 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 3 -Subparagraph (SX 210.12-04.(a)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24072-122690 + Details
Name: | us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition 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 in the second 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. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6802200&loc=d3e1835-112601 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 3 -Subparagraph (SX 210.12-04.(a)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24072-122690 + Details
Name: | us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Represents the current and noncurrent portions of a debt security issued by a state, certain agencies or authorities, a local government, or development corporation to finance the construction of air- or water-pollution control facilities or sewage or solid waste disposal facilities pursuant to federal law. The bonds are backed by the credit of the beneficiary of the financing rather than the credit of the issuer. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.16) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.20,22) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.16) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 + Details
Name: | us-gaap_LongtermPollutionControlBondCurrentAndNoncurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt. + References No definition available. + Details
Name: | us-gaap_ProceedsFromIssuanceOfDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Carrying value as of the balance sheet date of uncollateralized debt obligation (with maturities initially due after one year or beyond the operating cycle if longer), excluding current portion. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_UnsecuredLongTermDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_DebtInstrumentAxis=wec_FixedFirstAndRefundingMortgageXXSeries2.21PercentBondsDue2016Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=wec_FixedFirstAndRefundingMortgageRRSeries4.3PercentBondsDue2035Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=wec_Notessecurednonrecourse4.91due20142030MemberMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=wec_Notessecurednonrecourse6.00due20152033MemberMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=wec_Notessecurednonrecourse5.209due20132030MemberMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=wec_Notessecurednonrecourse4.673due20132031MemberMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=wec_UnsecuredSeniorNotes8PercentDue2016Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=wec_TEGJuniorSubordinatedNotes6.11due2066Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=wec_UnsecuredSeniorNotes4.17PercentDue2020Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=wec_NotesUnsecured620Due2033Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=wec_JuniorNotesUnsecured625Due2067Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=wec_TEGJuniorSubordinatedNotes6.00due2073Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=wec_WisconsinGasLLCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=wec_WGDebentures3.71due2046Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=wec_PGLMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=wec_PGL3.65SeriesDDDBondsdue2046Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=wec_PGL3.65SeriesCCCBondsdue2046Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=wec_WePowerLLCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=wec_IntegrysHoldingIncMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=us-gaap_ParentCompanyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |