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Income Taxes (Reconiliation of Income tax provision) (Details) - CAD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2019 | Dec. 31, 2018
Income before provision for income taxes | $ 771 | $ 816
Statutory income tax rate | 31.00% | 31.00%
Income taxes, at statutory income tax rates | $ 239 | $ 253
Deferred income taxes on regulated income recorded as regulatory assets and regulatory liabilities | (66) | (59)
Foreign tax rate variance | (49) | (55)
Amortization of deferred income tax regulatory liabilities | (36) | (37)
Florida state tax apportionment adjustment | 0 | (23)
Tax effect of equity earnings | (15) | (15)
GBPC impairment charge | 11 | 0
Investment tax credits | (9) | (4)
Change in treatment of NMGC net operating loss carryforwards | (7) | 0
Change in prior year unrecognized tax benefits at NSPI | 0 | 7
Other | (7) | 2
Income tax expense (recovery) | $ 61 | $ 69
Effective income tax rate | 8.00% | 8.00%

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