The amount of cash on hand and demand deposits, along with short-term, highly liquid investments that are readily convertible to known amounts of cash and that are subject to an insignificant risk of changes in value. [Refer: Cash; Cash equivalents]

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The amount of instruments issued by the entity that represent indebtedness.

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Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table.

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The amount of cash and cash equivalents whose use or withdrawal is restricted. [Refer: Cash and cash equivalents]

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Floating Rate Term Facility, Term

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Credit Facilities, Long-Term Debt and Lease Liabilities - Credit Facilities (Details) - CAD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disclosure of detailed information about borrowings [line items]
Cash and cash equivalents	$ 1,134	$ 947	$ 703	$ 411
Revolving Term Facility [Member]
Disclosure of detailed information about borrowings [line items]
Floating rate term	2 years
Letter of credit
Disclosure of detailed information about borrowings [line items]
Debt instruments issued	$ 218
Committed syndicated bank facility \| Committed credit facilities
Disclosure of detailed information about borrowings [line items]
Undrawn borrowing capacity	1,000	1,300
TransAlta OCP
Disclosure of detailed information about borrowings [line items]
Restricted cash	17	$ 17
Restricted cash principal amount	$ 17