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 Dividend Income Fund - Class A

Shareholder Report [Line Items]

Fund Name

Columbia Dividend Income Fund

Class Name

Class A

Trading Symbol

LBSAX

Annual or Semi-Annual Statement [Text Block]

This semiannual shareholder report contains important information about Columbia Dividend Income Fund (the Fund) for the period of June 1, 2024 to November 30, 2024.

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. You can also request more information by contacting us at 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	$47	0.89%(a)

(a) Annualized.

Expenses Paid, Amount

$ 47

Expense Ratio, Percent

0.89%

^[1]

Net Assets

$ 43,968,823,319

Holdings Count | Holding

77

Investment Company, Portfolio Turnover

8.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Fund net assets	$43,968,823,319
Total number of portfolio holdings	77
Portfolio turnover for the reporting period	8%

Holdings [Text Block]

Graphical Representation of Fund Holdings

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.

Top Holdings

JPMorgan Chase & Co.	4.3%
Microsoft Corp.	3.3%
UnitedHealth Group, Inc.	3.0%
Walmart, Inc.	2.9%
Home Depot, Inc. (The)	2.5%
Johnson & Johnson	2.4%
Exxon Mobil Corp.	2.3%
Procter & Gamble Co. (The)	2.2%
Broadcom, Inc.	2.2%
AbbVie, Inc.	2.1%

Asset Categories

Equity Sector Allocation

Largest Holdings [Text Block]

Top Holdings

JPMorgan Chase & Co.	4.3%
Microsoft Corp.	3.3%
UnitedHealth Group, Inc.	3.0%
Walmart, Inc.	2.9%
Home Depot, Inc. (The)	2.5%
Johnson & Johnson	2.4%
Exxon Mobil Corp.	2.3%
Procter & Gamble Co. (The)	2.2%
Broadcom, Inc.	2.2%
AbbVie, Inc.	2.1%

Columbia Dividend Income Fund - Class C

Shareholder Report [Line Items]

Fund Name

Columbia Dividend Income Fund

Class Name

Class C

Trading Symbol

LBSCX

Annual or Semi-Annual Statement [Text Block]

This semiannual shareholder report contains important information about Columbia Dividend Income Fund (the Fund) for the period of June 1, 2024 to November 30, 2024.

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. You can also request more information by contacting us at 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 C	$87	1.64%(a)

(a) Annualized.

Expenses Paid, Amount

$ 87

Expense Ratio, Percent

1.64%

^[1]

Net Assets

$ 43,968,823,319

Holdings Count | Holding

77

Investment Company, Portfolio Turnover

8.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Fund net assets	$43,968,823,319
Total number of portfolio holdings	77
Portfolio turnover for the reporting period	8%

Holdings [Text Block]

Graphical Representation of Fund Holdings

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.

Top Holdings

JPMorgan Chase & Co.	4.3%
Microsoft Corp.	3.3%
UnitedHealth Group, Inc.	3.0%
Walmart, Inc.	2.9%
Home Depot, Inc. (The)	2.5%
Johnson & Johnson	2.4%
Exxon Mobil Corp.	2.3%
Procter & Gamble Co. (The)	2.2%
Broadcom, Inc.	2.2%
AbbVie, Inc.	2.1%

Asset Categories

Equity Sector Allocation

Largest Holdings [Text Block]

Top Holdings

JPMorgan Chase & Co.	4.3%
Microsoft Corp.	3.3%
UnitedHealth Group, Inc.	3.0%
Walmart, Inc.	2.9%
Home Depot, Inc. (The)	2.5%
Johnson & Johnson	2.4%
Exxon Mobil Corp.	2.3%
Procter & Gamble Co. (The)	2.2%
Broadcom, Inc.	2.2%
AbbVie, Inc.	2.1%

Columbia Dividend Income Fund - Institutional Class

Shareholder Report [Line Items]

Fund Name

Columbia Dividend Income Fund

Class Name

Institutional Class

Trading Symbol

GSFTX

Annual or Semi-Annual Statement [Text Block]

This semiannual shareholder report contains important information about Columbia Dividend Income Fund (the Fund) for the period of June 1, 2024 to November 30, 2024.

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. You can also request more information by contacting us at 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	$34	0.64%(a)

(a) Annualized.

Expenses Paid, Amount

$ 34

Expense Ratio, Percent

0.64%

^[1]

Net Assets

$ 43,968,823,319

Holdings Count | Holding

77

Investment Company, Portfolio Turnover

8.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Fund net assets	$43,968,823,319
Total number of portfolio holdings	77
Portfolio turnover for the reporting period	8%

Holdings [Text Block]

Graphical Representation of Fund Holdings

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.

Top Holdings

JPMorgan Chase & Co.	4.3%
Microsoft Corp.	3.3%
UnitedHealth Group, Inc.	3.0%
Walmart, Inc.	2.9%
Home Depot, Inc. (The)	2.5%
Johnson & Johnson	2.4%
Exxon Mobil Corp.	2.3%
Procter & Gamble Co. (The)	2.2%
Broadcom, Inc.	2.2%
AbbVie, Inc.	2.1%

Asset Categories

Equity Sector Allocation

Largest Holdings [Text Block]

Top Holdings

JPMorgan Chase & Co.	4.3%
Microsoft Corp.	3.3%
UnitedHealth Group, Inc.	3.0%
Walmart, Inc.	2.9%
Home Depot, Inc. (The)	2.5%
Johnson & Johnson	2.4%
Exxon Mobil Corp.	2.3%
Procter & Gamble Co. (The)	2.2%
Broadcom, Inc.	2.2%
AbbVie, Inc.	2.1%

Columbia Dividend Income Fund - Institutional 2 Class

Shareholder Report [Line Items]

Fund Name

Columbia Dividend Income Fund

Class Name

Institutional 2 Class

Trading Symbol

CDDRX

Annual or Semi-Annual Statement [Text Block]

This semiannual shareholder report contains important information about Columbia Dividend Income Fund (the Fund) for the period of June 1, 2024 to November 30, 2024.

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. You can also request more information by contacting us at 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 2 Class	$31	0.59%(a)

(a) Annualized.

Expenses Paid, Amount

$ 31

Expense Ratio, Percent

0.59%

^[1]

Net Assets

$ 43,968,823,319

Holdings Count | Holding

77

Investment Company, Portfolio Turnover

8.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Fund net assets	$43,968,823,319
Total number of portfolio holdings	77
Portfolio turnover for the reporting period	8%

Holdings [Text Block]

Graphical Representation of Fund Holdings

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.

Top Holdings

JPMorgan Chase & Co.	4.3%
Microsoft Corp.	3.3%
UnitedHealth Group, Inc.	3.0%
Walmart, Inc.	2.9%
Home Depot, Inc. (The)	2.5%
Johnson & Johnson	2.4%
Exxon Mobil Corp.	2.3%
Procter & Gamble Co. (The)	2.2%
Broadcom, Inc.	2.2%
AbbVie, Inc.	2.1%

Asset Categories

Equity Sector Allocation

Largest Holdings [Text Block]

Top Holdings

JPMorgan Chase & Co.	4.3%
Microsoft Corp.	3.3%
UnitedHealth Group, Inc.	3.0%
Walmart, Inc.	2.9%
Home Depot, Inc. (The)	2.5%
Johnson & Johnson	2.4%
Exxon Mobil Corp.	2.3%
Procter & Gamble Co. (The)	2.2%
Broadcom, Inc.	2.2%
AbbVie, Inc.	2.1%

Columbia Dividend Income Fund - Institutional 3 Class

Shareholder Report [Line Items]

Fund Name

Columbia Dividend Income Fund

Class Name

Institutional 3 Class

Trading Symbol

CDDYX

Annual or Semi-Annual Statement [Text Block]

This semiannual shareholder report contains important information about Columbia Dividend Income Fund (the Fund) for the period of June 1, 2024 to November 30, 2024.

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. You can also request more information by contacting us at 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 3 Class	$29	0.54%(a)

(a) Annualized.

Expenses Paid, Amount

$ 29

Expense Ratio, Percent

0.54%

^[1]

Net Assets

$ 43,968,823,319

Holdings Count | Holding

77

Investment Company, Portfolio Turnover

8.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Fund net assets	$43,968,823,319
Total number of portfolio holdings	77
Portfolio turnover for the reporting period	8%

Holdings [Text Block]

Graphical Representation of Fund Holdings

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.

Top Holdings

JPMorgan Chase & Co.	4.3%
Microsoft Corp.	3.3%
UnitedHealth Group, Inc.	3.0%
Walmart, Inc.	2.9%
Home Depot, Inc. (The)	2.5%
Johnson & Johnson	2.4%
Exxon Mobil Corp.	2.3%
Procter & Gamble Co. (The)	2.2%
Broadcom, Inc.	2.2%
AbbVie, Inc.	2.1%

Asset Categories

Equity Sector Allocation

Largest Holdings [Text Block]

Top Holdings

JPMorgan Chase & Co.	4.3%
Microsoft Corp.	3.3%
UnitedHealth Group, Inc.	3.0%
Walmart, Inc.	2.9%
Home Depot, Inc. (The)	2.5%
Johnson & Johnson	2.4%
Exxon Mobil Corp.	2.3%
Procter & Gamble Co. (The)	2.2%
Broadcom, Inc.	2.2%
AbbVie, Inc.	2.1%

Columbia Dividend Income Fund - Class R

Shareholder Report [Line Items]

Fund Name

Columbia Dividend Income Fund

Class Name

Class R

Trading Symbol

CDIRX

Annual or Semi-Annual Statement [Text Block]

This semiannual shareholder report contains important information about Columbia Dividend Income Fund (the Fund) for the period of June 1, 2024 to November 30, 2024.

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. You can also request more information by contacting us at 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 R	$60	1.14%(a)

(a) Annualized.

Expenses Paid, Amount

$ 60

Expense Ratio, Percent

1.14%

^[1]

Net Assets

$ 43,968,823,319

Holdings Count | Holding

77

Investment Company, Portfolio Turnover

8.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Fund net assets	$43,968,823,319
Total number of portfolio holdings	77
Portfolio turnover for the reporting period	8%

Holdings [Text Block]

Graphical Representation of Fund Holdings

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.

Top Holdings

JPMorgan Chase & Co.	4.3%
Microsoft Corp.	3.3%
UnitedHealth Group, Inc.	3.0%
Walmart, Inc.	2.9%
Home Depot, Inc. (The)	2.5%
Johnson & Johnson	2.4%
Exxon Mobil Corp.	2.3%
Procter & Gamble Co. (The)	2.2%
Broadcom, Inc.	2.2%
AbbVie, Inc.	2.1%

Asset Categories

Equity Sector Allocation

Largest Holdings [Text Block]

Top Holdings

JPMorgan Chase & Co.	4.3%
Microsoft Corp.	3.3%
UnitedHealth Group, Inc.	3.0%
Walmart, Inc.	2.9%
Home Depot, Inc. (The)	2.5%
Johnson & Johnson	2.4%
Exxon Mobil Corp.	2.3%
Procter & Gamble Co. (The)	2.2%
Broadcom, Inc.	2.2%
AbbVie, Inc.	2.1%

Columbia Dividend Income Fund - Class S

Shareholder Report [Line Items]

Fund Name

Columbia Dividend Income Fund

Class Name

Class S

Trading Symbol

GFSDX

Annual or Semi-Annual Statement [Text Block]

This semiannual shareholder report contains important information about Columbia Dividend Income Fund (the Fund) for the period of October 2, 2024 to November 30, 2024.

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. You can also request more information by contacting us at 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 S	$11(a)	0.68%(b)

(a)	Based on operations from October 2, 2024 (commencement of operations) through the stated period end. Had the class been open for the entire reporting period, expenses shown in the table above would have been higher.
(b)	Annualized.

Expenses Paid, Amount

$ 11

^[2]

Expense Ratio, Percent

0.68%

^[1]

Net Assets

$ 43,968,823,319

Holdings Count | Holding

77

Investment Company, Portfolio Turnover

8.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Fund net assets	$43,968,823,319
Total number of portfolio holdings	77
Portfolio turnover for the reporting period	8%

Holdings [Text Block]

Graphical Representation of Fund Holdings

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.

Top Holdings

JPMorgan Chase & Co.	4.3%
Microsoft Corp.	3.3%
UnitedHealth Group, Inc.	3.0%
Walmart, Inc.	2.9%
Home Depot, Inc. (The)	2.5%
Johnson & Johnson	2.4%
Exxon Mobil Corp.	2.3%
Procter & Gamble Co. (The)	2.2%
Broadcom, Inc.	2.2%
AbbVie, Inc.	2.1%

Asset Categories

Equity Sector Allocation

Largest Holdings [Text Block]

Top Holdings

JPMorgan Chase & Co.	4.3%
Microsoft Corp.	3.3%
UnitedHealth Group, Inc.	3.0%
Walmart, Inc.	2.9%
Home Depot, Inc. (The)	2.5%
Johnson & Johnson	2.4%
Exxon Mobil Corp.	2.3%
Procter & Gamble Co. (The)	2.2%
Broadcom, Inc.	2.2%
AbbVie, Inc.	2.1%

[1] Annualized.

[2] Based on operations from October 2, 2024 (commencement of operations) through the stated period end. Had the class been open for the entire reporting period, expenses shown in the table above would have been higher.