CONSOLIDATED STATEMENT OF STOCKHOLDERS' EQUITY - CAD ($) shares in Millions, $ in Millions	Total	Preferred Shares	Equity attributable to Kinder Morgan pre-IPO	Restricted Voting Share capital	Retained earnings (deficit)	Accumulated other comprehensive loss	Kinder Morgan interest	Restricted Voting Shares Voting Shares	Special Voting Shares Voting Shares
Stockholders' Equity, beginning balance at Dec. 31, 2015	$ 1,251.0		$ 1,464.3		$ (193.8)	$ (19.5)
Activity attributable to Kinder Morgan prior to IPO-Equity interests issued	10.7		10.7
Activity attributable to Kinder Morgan prior to IPO, Distribution	(21.1)				(21.1)
Net income including portion attributable to Kinder Morgan interest	201.8				201.8
Other comprehensive income (loss)	(6.4)					(6.4)
Preferred stock, shares outstanding (in shares), ending balance at Dec. 31, 2016		0.0
Voting shares, shares outstanding (in shares), ending balance at Dec. 31, 2016								0.0	0.0
Stockholders' Equity, ending balance at Dec. 31, 2016	1,436.0	$ 0.0	1,475.0	$ 0.0	(13.1)	(25.9)	$ 0.0
Activity attributable to Kinder Morgan prior to IPO-Equity interests issued	126.9		126.9
Activity attributable to Kinder Morgan prior to IPO, Distribution	(261.7)		(261.7)
Net income including portion attributable to Kinder Morgan interest	160.7				34.5		126.2
Dividends, Preferred Stock, Cash	4.0				4.0
Restricted voting share dividends	(22.8)				(22.8)
Special Voting Share Distributions	(55.1)						(55.1)
Stock Issued During Period, Shares, Dividend Reinvestment Plan								0.2	0.3
Stock Issued During Period, Value, Dividend Reinvestment Plan	20.0			6.7			13.3
Stock-based compensation	2.2			2.2
Stock Issued During Period, Shares, New Issues		22.0						34.3	80.7
Stock Issued During Period, Value, New Issues	1,750.0			1,750.0
Preferred Stock Issued During Period, Value, New Issues	550.0	$ 550.0
Issuance of special voting shares and reallocation of Kinder Morgan pre-IPO carrying basis	0.0		(1,340.2)		13.1	25.9	1,301.2
Reallocation of equity on Common Control transaction	0.0				(777.7)	(7.5)	785.2
Equity Issuance fees	(83.8)	(13.9)		(69.9)
Deferred tax liability adjustments	(22.7)	$ (1.1)		(18.8)			(2.8)
Other	0.0			0.3			(0.3)
Other comprehensive income (loss)	(3.5)					(1.3)	(2.2)
Preferred stock, shares outstanding (in shares), ending balance at Dec. 31, 2017		22.0
Voting shares, shares outstanding (in shares), ending balance at Dec. 31, 2017								34.5	81.0
Stockholders' Equity, ending balance at Dec. 31, 2017	3,637.6	$ 537.2	$ 0.0	1,707.5	(770.0)	(8.8)	2,171.7
Net income including portion attributable to Kinder Morgan interest	1,418.2				445.0		973.2
Preferred share dividends	(27.7)				(27.7)
Restricted voting share dividends	(68.0)				(68.0)
Special Voting Share Distributions	(161.8)						(161.8)
Return of Capital(Note 3)	(3,977.4)				(1,195.1)		(2,782.3)
Stock Issued During Period, Shares, Dividend Reinvestment Plan								0.4	0.4
Stock Issued During Period, Value, Dividend Reinvestment Plan	37.8			18.0			19.8
Stock-based compensation	4.5			4.5
Stated Capital Reduction(Note 3)	0.0			(1,450.0)	1,450.0
Other				(1.9)			1.9
Other comprehensive income (loss)	29.3					8.8	20.5
Preferred stock, shares outstanding (in shares), ending balance at Dec. 31, 2018		22.0
Voting shares, shares outstanding (in shares), ending balance at Dec. 31, 2018								34.9	81.4
Stockholders' Equity, ending balance at Dec. 31, 2018	$ 892.5	$ 537.2		$ 278.1	$ (165.8)	$ 0.0	$ 243.0