Columbia Balanced Fund (CBALX) N-CSRS 3 Feb 25 Certified semi-annual shareholder report (management investment company) Financial data

Form N-CSR Cover

Form N-CSR Cover	6 Months Ended
	Nov. 30, 2024
Shareholder Report [Line Items]
Document Type	N-CSRS
Amendment Flag	false
Registrant Name	Columbia Funds Series Trust I
Entity Central Index Key	0000773757
Entity Investment Company Type	N-1A
Document Period End Date	Nov. 30, 2024

Shareholder Report

Shareholder Report	6 Months Ended
	Nov. 30, 2024 USD ($) Holding
Shareholder Report [Line Items]
Document Type	N-CSRS
Amendment Flag	false
Registrant Name	Columbia Funds Series Trust I
Entity Central Index Key	0000773757
Entity Investment Company Type	N-1A
Document Period End Date	Nov. 30, 2024
Columbia Multi Strategy Alternatives Fund - Class A
Shareholder Report [Line Items]
Fund Name	Columbia Multi Strategy Alternatives Fund
Class Name	Class A
Trading Symbol	CLAAX
Annual or Semi-Annual Statement [Text Block]	This semiannual shareholder report
Shareholder Report Annual or Semi-Annual	semi-annual shareholder report
Additional Information [Text Block]	You can find additional information about the Fund at columbiathreadneedleus.com/resources/literature 1-800-345-6611.
Additional Information Phone Number	1-800-345-6611
Additional Information Website	columbiathreadneedleus.com/resources/literature
Expenses [Text Block]	What were the Fund costs for the reporting period? (Based on a hypothetical $10,000 investment) Class Cost of a $10,000 investment Cost paid as a percentage of a $10,000 investment Class A $ 1.36 % (a) (a) Annualized.
Expenses Paid, Amount	$ 68
Expense Ratio, Percent	1.36%	[1]
Net Assets	$ 522,181,715
Holdings Count | Holding	1,048
Investment Company, Portfolio Turnover	364%
Additional Fund Statistics [Text Block]	Key Fund Statistics Fund net assets $ Total number of portfolio holdings 1,048 Portfolio turnover for the reporting period 364% Portfolio turnover for the reporting period excluding to be announced (TBA) securities 9%
Holdings [Text Block]	Graphical Representation of Fund The tables below show the investment makeup of the Derivative Exposure Long Commodity-Related Investment Risk 34.8 % Credit Risk 0.7 % Equity Risk 38.9 % Foreign Exchange Risk 379.4 % Interest Rate Risk 274.4 % Short Commodity-Related Investment Risk 30.0 % Credit Risk 1.1 % Equity Risk 38.9 % Foreign Exchange Risk 318.3 % Interest Rate Risk 290.1 % Asset Categories
Columbia Multi Strategy Alternatives Fund - Class C
Shareholder Report [Line Items]
Fund Name	Columbia Multi Strategy Alternatives Fund
Class Name	Class C
Trading Symbol	CLABX
Annual or Semi-Annual Statement [Text Block]	This semiannual shareholder report
Shareholder Report Annual or Semi-Annual	semi-annual shareholder report
Additional Information [Text Block]	You can find additional information about the Fund at columbiathreadneedleus.com/resources/literature 1-800-345-6611.
Additional Information Phone Number	1-800-345-6611
Additional Information Website	columbiathreadneedleus.com/resources/literature
Expenses [Text Block]	What were the Fund costs for the reporting (Based on a hypothetical $10,000 investment) Class Cost of a $10,000 investment Cost paid as a percentage of a $10,000 investment Class C $ 2.11 % (a) (a) Annualized.
Expenses Paid, Amount	$ 105
Expense Ratio, Percent	2.11%	[1]
Net Assets	$ 522,181,715
Holdings Count | Holding	1,048
Investment Company, Portfolio Turnover	364%
Additional Fund Statistics [Text Block]	Key Fund Statistics Fund net assets $ Total number of portfolio holdings 1,048 Portfolio turnover for the reporting period 364% Portfolio turnover for the reporting period excluding to be announced (TBA) securities 9%
Holdings [Text Block]	Graphical Representation of Fund The tables below show the investment makeup of the Fund represented as a percentage of Fund net assets. Derivatives are excluded from the tables unless otherwise noted. The Fund's portfolio composition is subject to change. Derivative Exposure Long Commodity-Related Investment Risk 34.8 % Credit Risk 0.7 % Equity Risk 38.9 % Foreign Exchange Risk 379.4 % Interest Rate Risk 274.4 % Short Commodity-Related Investment Risk 30.0 % Credit Risk 1.1 % Equity Risk 38.9 % Foreign Exchange Risk 318.3 % Interest Rate Risk 290.1 % Asset Categories
Columbia Multi Strategy Alternatives Fund - Institutional Class
Shareholder Report [Line Items]
Fund Name	Columbia Multi Strategy Alternatives Fund
Class Name	Institutional Class
Trading Symbol	CLAZX
Annual or Semi-Annual Statement [Text Block]	This semiannual shareholder report
Shareholder Report Annual or Semi-Annual	semi-annual shareholder report
Additional Information [Text Block]	You can find additional information about the Fund at columbiathreadneedleus.com/resources/literature 1-800-345-6611.
Additional Information Phone Number	1-800-345-6611
Additional Information Website	columbiathreadneedleus.com/resources/literature
Expenses [Text Block]	What were the Fund costs for the reporting period? (Based on a hypothetical $10,000 investment) Class Cost of a $10,000 investment Cost paid as a percentage of a $10,000 investment Institutional Class $ 1.11 % (a) (a) Annualized.
Expenses Paid, Amount	$ 55
Expense Ratio, Percent	1.11%	[1]
Net Assets	$ 522,181,715
Holdings Count | Holding	1,048
Investment Company, Portfolio Turnover	364%
Additional Fund Statistics [Text Block]	Key Fund Statistics Fund net assets $ Total number of portfolio holdings 1,048 Portfolio turnover for the reporting period 364% Portfolio turnover for the reporting period excluding to be announced (TBA) securities 9%
Holdings [Text Block]	Graphical Representation of Fund The tables below show the investment makeup of the Fund represented Fund's Derivative Exposure Long Commodity-Related Investment Risk 34.8 % Credit Risk 0.7 % Equity Risk 38.9 % Foreign Exchange Risk 379.4 % Interest Rate Risk 274.4 % Short Commodity-Related Investment Risk 30.0 % Credit Risk 1.1 % Equity Risk 38.9 % Foreign Exchange Risk 318.3 % Interest Rate Risk 290.1 % Asset Categories
[1]Annualized.

Shareholder Report, Holdings (D

Shareholder Report, Holdings (Details)	Nov. 30, 2024
Columbia Multi Strategy Alternatives Fund - Class A | Long Commodity-Related Investment Risk [Member]
Holdings [Line Items]
Percent of Net Asset Value	34.80%
Columbia Multi Strategy Alternatives Fund - Class A | Long Credit Risk [Member]
Holdings [Line Items]
Percent of Net Asset Value	0.70%
Columbia Multi Strategy Alternatives Fund - Class A | Long Equity Risk [Member]
Holdings [Line Items]
Percent of Net Asset Value	38.90%
Columbia Multi Strategy Alternatives Fund - Class A | Long Foreign Exchange Risk [Member]
Holdings [Line Items]
Percent of Net Asset Value	379.40%
Columbia Multi Strategy Alternatives Fund - Class A | Long Interest Rate Risk [Member]
Holdings [Line Items]
Percent of Net Asset Value	274.40%
Columbia Multi Strategy Alternatives Fund - Class A | Short Commodity-Related Investment Risk [Member]
Holdings [Line Items]
Percent of Net Asset Value	30%
Columbia Multi Strategy Alternatives Fund - Class A | Short Credit Risk [Member]
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Columbia Multi Strategy Alternatives Fund - Class A | Short Equity Risk [Member]
Holdings [Line Items]
Percent of Net Asset Value	38.90%
Columbia Multi Strategy Alternatives Fund - Class A | Short Foreign Exchange Risk [Member]
Holdings [Line Items]
Percent of Net Asset Value	318.30%
Columbia Multi Strategy Alternatives Fund - Class A | Short Interest Rate Risk [Member]
Holdings [Line Items]
Percent of Net Asset Value	290.10%
Columbia Multi Strategy Alternatives Fund - Class A | Money Market Fund [Member]
Holdings [Line Items]
Percent of Net Asset Value	44.10%
Columbia Multi Strategy Alternatives Fund - Class A | Residential Mortgage-Backed Securities - Agency [Member]
Holdings [Line Items]
Percent of Net Asset Value	37.70%
Columbia Multi Strategy Alternatives Fund - Class A | Treasury Bills [Member]
Holdings [Line Items]
Percent of Net Asset Value	16.40%
Columbia Multi Strategy Alternatives Fund - Class A | Residential Mortgage-Backed Securities - Non Agency [Member]
Holdings [Line Items]
Percent of Net Asset Value	14.90%
Columbia Multi Strategy Alternatives Fund - Class A | Asset-Backed Securities - Non-Agency [Member]
Holdings [Line Items]
Percent of Net Asset Value	4%
Columbia Multi Strategy Alternatives Fund - Class A | Commercial Mortgage-Backed Securities - Non-Agency [Member]
Holdings [Line Items]
Percent of Net Asset Value	1%
Columbia Multi Strategy Alternatives Fund - Class A | Other [Member]
Holdings [Line Items]
Percent of Net Asset Value	0.30%
Columbia Multi Strategy Alternatives Fund - Class C | Long Commodity-Related Investment Risk [Member]
Holdings [Line Items]
Percent of Net Asset Value	34.80%
Columbia Multi Strategy Alternatives Fund - Class C | Long Credit Risk [Member]
Holdings [Line Items]
Percent of Net Asset Value	0.70%
Columbia Multi Strategy Alternatives Fund - Class C | Long Equity Risk [Member]
Holdings [Line Items]
Percent of Net Asset Value	38.90%
Columbia Multi Strategy Alternatives Fund - Class C | Long Foreign Exchange Risk [Member]
Holdings [Line Items]
Percent of Net Asset Value	379.40%
Columbia Multi Strategy Alternatives Fund - Class C | Long Interest Rate Risk [Member]
Holdings [Line Items]
Percent of Net Asset Value	274.40%
Columbia Multi Strategy Alternatives Fund - Class C | Short Commodity-Related Investment Risk [Member]
Holdings [Line Items]
Percent of Net Asset Value	30%
Columbia Multi Strategy Alternatives Fund - Class C | Short Credit Risk [Member]
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Columbia Multi Strategy Alternatives Fund - Class C | Short Equity Risk [Member]
Holdings [Line Items]
Percent of Net Asset Value	38.90%
Columbia Multi Strategy Alternatives Fund - Class C | Short Foreign Exchange Risk [Member]
Holdings [Line Items]
Percent of Net Asset Value	318.30%
Columbia Multi Strategy Alternatives Fund - Class C | Short Interest Rate Risk [Member]
Holdings [Line Items]
Percent of Net Asset Value	290.10%
Columbia Multi Strategy Alternatives Fund - Class C | Money Market Fund [Member]
Holdings [Line Items]
Percent of Net Asset Value	44.10%
Columbia Multi Strategy Alternatives Fund - Class C | Residential Mortgage-Backed Securities - Agency [Member]
Holdings [Line Items]
Percent of Net Asset Value	37.70%
Columbia Multi Strategy Alternatives Fund - Class C | Treasury Bills [Member]
Holdings [Line Items]
Percent of Net Asset Value	16.40%
Columbia Multi Strategy Alternatives Fund - Class C | Residential Mortgage-Backed Securities - Non Agency [Member]
Holdings [Line Items]
Percent of Net Asset Value	14.90%
Columbia Multi Strategy Alternatives Fund - Class C | Asset-Backed Securities - Non-Agency [Member]
Holdings [Line Items]
Percent of Net Asset Value	4%
Columbia Multi Strategy Alternatives Fund - Class C | Commercial Mortgage-Backed Securities - Non-Agency [Member]
Holdings [Line Items]
Percent of Net Asset Value	1%
Columbia Multi Strategy Alternatives Fund - Class C | Other [Member]
Holdings [Line Items]
Percent of Net Asset Value	0.30%
Columbia Multi Strategy Alternatives Fund - Institutional Class | Long Commodity-Related Investment Risk [Member]
Holdings [Line Items]
Percent of Net Asset Value	34.80%
Columbia Multi Strategy Alternatives Fund - Institutional Class | Long Credit Risk [Member]
Holdings [Line Items]
Percent of Net Asset Value	0.70%
Columbia Multi Strategy Alternatives Fund - Institutional Class | Long Equity Risk [Member]
Holdings [Line Items]
Percent of Net Asset Value	38.90%
Columbia Multi Strategy Alternatives Fund - Institutional Class | Long Foreign Exchange Risk [Member]
Holdings [Line Items]
Percent of Net Asset Value	379.40%
Columbia Multi Strategy Alternatives Fund - Institutional Class | Long Interest Rate Risk [Member]
Holdings [Line Items]
Percent of Net Asset Value	274.40%
Columbia Multi Strategy Alternatives Fund - Institutional Class | Short Commodity-Related Investment Risk [Member]
Holdings [Line Items]
Percent of Net Asset Value	30%
Columbia Multi Strategy Alternatives Fund - Institutional Class | Short Credit Risk [Member]
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Columbia Multi Strategy Alternatives Fund - Institutional Class | Short Equity Risk [Member]
Holdings [Line Items]
Percent of Net Asset Value	38.90%
Columbia Multi Strategy Alternatives Fund - Institutional Class | Short Foreign Exchange Risk [Member]
Holdings [Line Items]
Percent of Net Asset Value	318.30%
Columbia Multi Strategy Alternatives Fund - Institutional Class | Short Interest Rate Risk [Member]
Holdings [Line Items]
Percent of Net Asset Value	290.10%
Columbia Multi Strategy Alternatives Fund - Institutional Class | Money Market Fund [Member]
Holdings [Line Items]
Percent of Net Asset Value	44.10%
Columbia Multi Strategy Alternatives Fund - Institutional Class | Residential Mortgage-Backed Securities - Agency [Member]
Holdings [Line Items]
Percent of Net Asset Value	37.70%
Columbia Multi Strategy Alternatives Fund - Institutional Class | Treasury Bills [Member]
Holdings [Line Items]
Percent of Net Asset Value	16.40%
Columbia Multi Strategy Alternatives Fund - Institutional Class | Residential Mortgage-Backed Securities - Non Agency [Member]
Holdings [Line Items]
Percent of Net Asset Value	14.90%
Columbia Multi Strategy Alternatives Fund - Institutional Class | Asset-Backed Securities - Non-Agency [Member]
Holdings [Line Items]
Percent of Net Asset Value	4%
Columbia Multi Strategy Alternatives Fund - Institutional Class | Commercial Mortgage-Backed Securities - Non-Agency [Member]
Holdings [Line Items]
Percent of Net Asset Value	1%
Columbia Multi Strategy Alternatives Fund - Institutional Class | Other [Member]
Holdings [Line Items]
Percent of Net Asset Value	0.30%