This semi-annual shareholder report contains important information about California High-Yield Municipal Fund for the period of September 1, 2025 to February 28, 2026.

Shareholder Report Annual or Semi-Annual

semi-annual shareholder report

Additional Information [Text Block]

You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.

Additional Information Phone Number

1-800-345-2021

Additional Information Website

americancentury.com/docs

Expenses [Text Block]


What were the fund costs for the last six months? (based on a hypothetical $10,000 investment)

	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Investor Class	$25	0.49%

Expenses Paid, Amount

$ 25

Expense Ratio, Percent

0.49%

Net Assets

$ 1,643,061,596

Holdings Count | holding

666

Advisory Fees Paid, Amount

$ 3,057,095

Investment Company, Portfolio Turnover

20.00%

Holdings [Text Block]


Fund Holdings


			Types of Investments in Portfolio (as a % of net assets)
			Municipal Securities			98.5%
			Affiliated Funds			0.5%
			Warrants			0.0%
			Other Assets and Liabilities			1.0%

C000087984 [Member]

Shareholder Report [Line Items]

Fund Name

California High-Yield Municipal Fund

Class Name

I Class

Trading Symbol

BCHIX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about California High-Yield Municipal Fund for the period of September 1, 2025 to February 28, 2026.

Shareholder Report Annual or Semi-Annual

semi-annual shareholder report

Additional Information [Text Block]

You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.

Additional Information Phone Number

1-800-345-2021

Additional Information Website

americancentury.com/docs

Expenses [Text Block]


What were the fund costs for the last six months? (based on a hypothetical $10,000 investment)

	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
I Class	$15	0.29%

Expenses Paid, Amount

$ 15

Expense Ratio, Percent

0.29%

Net Assets

$ 1,643,061,596

Holdings Count | holding

666

Advisory Fees Paid, Amount

$ 3,057,095

Investment Company, Portfolio Turnover

20.00%

Holdings [Text Block]


Fund Holdings


			Types of Investments in Portfolio (as a % of net assets)
			Municipal Securities			98.5%
			Affiliated Funds			0.5%
			Warrants			0.0%
			Other Assets and Liabilities			1.0%

C000189669 [Member]

Shareholder Report [Line Items]

Fund Name

California High-Yield Municipal Fund

Class Name

Y Class

Trading Symbol

ACYHX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about California High-Yield Municipal Fund for the period of September 1, 2025 to February 28, 2026.

Shareholder Report Annual or Semi-Annual

semi-annual shareholder report

Additional Information [Text Block]

You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.

Additional Information Phone Number

1-800-345-2021

Additional Information Website

americancentury.com/docs

Expenses [Text Block]


What were the fund costs for the last six months? (based on a hypothetical $10,000 investment)

	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Y Class	$13	0.26%

Expenses Paid, Amount

$ 13

Expense Ratio, Percent

0.26%

Net Assets

$ 1,643,061,596

Holdings Count | holding

666

Advisory Fees Paid, Amount

$ 3,057,095

Investment Company, Portfolio Turnover

20.00%

Holdings [Text Block]


Fund Holdings


			Types of Investments in Portfolio (as a % of net assets)
			Municipal Securities			98.5%
			Affiliated Funds			0.5%
			Warrants			0.0%
			Other Assets and Liabilities			1.0%

C000015522 [Member]

Shareholder Report [Line Items]

Fund Name

California High-Yield Municipal Fund

Class Name

A Class

Trading Symbol

CAYAX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about California High-Yield Municipal Fund for the period of September 1, 2025 to February 28, 2026.

Shareholder Report Annual or Semi-Annual

semi-annual shareholder report

Additional Information [Text Block]

You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.

Additional Information Phone Number

1-800-345-2021

Additional Information Website

americancentury.com/docs

Expenses [Text Block]


What were the fund costs for the last six months? (based on a hypothetical $10,000 investment)

	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
A Class	$38	0.74%

Expenses Paid, Amount

$ 38

Expense Ratio, Percent

0.74%

Net Assets

$ 1,643,061,596

Holdings Count | holding

666

Advisory Fees Paid, Amount

$ 3,057,095

Investment Company, Portfolio Turnover

20.00%

Holdings [Text Block]


Fund Holdings


			Types of Investments in Portfolio (as a % of net assets)
			Municipal Securities			98.5%
			Affiliated Funds			0.5%
			Warrants			0.0%
			Other Assets and Liabilities			1.0%

C000015524 [Member]

Shareholder Report [Line Items]

Fund Name

California High-Yield Municipal Fund

Class Name

C Class

Trading Symbol

CAYCX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about California High-Yield Municipal Fund for the period of September 1, 2025 to February 28, 2026.

Shareholder Report Annual or Semi-Annual

semi-annual shareholder report

Additional Information [Text Block]

You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.

Additional Information Phone Number

1-800-345-2021

Additional Information Website

americancentury.com/docs

Expenses [Text Block]


What were the fund costs for the last six months? (based on a hypothetical $10,000 investment)

	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
C Class	$76	1.49%

Expenses Paid, Amount

$ 76

Expense Ratio, Percent

1.49%

Net Assets

$ 1,643,061,596

Holdings Count | holding

666

Advisory Fees Paid, Amount

$ 3,057,095

Investment Company, Portfolio Turnover

20.00%

Holdings [Text Block]


Fund Holdings


			Types of Investments in Portfolio (as a % of net assets)
			Municipal Securities			98.5%
			Affiliated Funds			0.5%
			Warrants			0.0%
			Other Assets and Liabilities			1.0%

C000015525 [Member]

Shareholder Report [Line Items]

Fund Name

California Intermediate-Term Tax-Free Bond Fund

Class Name

Investor Class

Trading Symbol

BCITX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about California Intermediate-Term Tax-Free Bond Fund for the period of September 1, 2025 to February 28, 2026.

Shareholder Report Annual or Semi-Annual

semi-annual shareholder report

Additional Information [Text Block]

You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.

Additional Information Phone Number

1-800-345-2021

Additional Information Website

americancentury.com/docs

Expenses [Text Block]


What were the fund costs for the last six months? (based on a hypothetical $10,000 investment)

	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Investor Class	$23	0.46%

Expenses Paid, Amount

$ 23

Expense Ratio, Percent

0.46%

Net Assets

$ 2,221,727,663

Holdings Count | holding

1,052

Advisory Fees Paid, Amount

$ 3,234,198

Investment Company, Portfolio Turnover

15.00%

Holdings [Text Block]


Fund Holdings


			Types of Investments in Portfolio (as a % of net assets)
			Municipal Securities			100.8%
			Affiliated Funds			0.5%
			Other Assets and Liabilities			(1.3)%

C000087985 [Member]

Shareholder Report [Line Items]

Fund Name

California Intermediate-Term Tax-Free Bond Fund

Class Name

I Class

Trading Symbol

BCTIX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about California Intermediate-Term Tax-Free Bond Fund for the period of September 1, 2025 to February 28, 2026.

Shareholder Report Annual or Semi-Annual

semi-annual shareholder report

Additional Information [Text Block]

You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.

Additional Information Phone Number

1-800-345-2021

Additional Information Website

americancentury.com/docs

Expenses [Text Block]


What were the fund costs for the last six months? (based on a hypothetical $10,000 investment)

	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
I Class	$13	0.26%

Expenses Paid, Amount

$ 13

Expense Ratio, Percent

0.26%

Net Assets

$ 2,221,727,663

Holdings Count | holding

1,052

Advisory Fees Paid, Amount

$ 3,234,198

Investment Company, Portfolio Turnover

15.00%

Holdings [Text Block]


Fund Holdings


			Types of Investments in Portfolio (as a % of net assets)
			Municipal Securities			100.8%
			Affiliated Funds			0.5%
			Other Assets and Liabilities			(1.3)%

C000189670 [Member]

Shareholder Report [Line Items]

Fund Name

California Intermediate-Term Tax-Free Bond Fund

Class Name

Y Class

Trading Symbol

ACYTX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about California Intermediate-Term Tax-Free Bond Fund for the period of September 1, 2025 to February 28, 2026.

Shareholder Report Annual or Semi-Annual

semi-annual shareholder report

Additional Information [Text Block]

You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.

Additional Information Phone Number

1-800-345-2021

Additional Information Website

americancentury.com/docs

Expenses [Text Block]


What were the fund costs for the last six months? (based on a hypothetical $10,000 investment)

	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Y Class	$12	0.23%

Expenses Paid, Amount

$ 12

Expense Ratio, Percent

0.23%

Net Assets

$ 2,221,727,663

Holdings Count | holding

1,052

Advisory Fees Paid, Amount

$ 3,234,198

Investment Company, Portfolio Turnover

15.00%

Holdings [Text Block]


Fund Holdings


			Types of Investments in Portfolio (as a % of net assets)
			Municipal Securities			100.8%
			Affiliated Funds			0.5%
			Other Assets and Liabilities			(1.3)%

C000087986 [Member]

Shareholder Report [Line Items]

Fund Name

California Intermediate-Term Tax-Free Bond Fund

Class Name

A Class

Trading Symbol

BCIAX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about California Intermediate-Term Tax-Free Bond Fund for the period of September 1, 2025 to February 28, 2026.

Shareholder Report Annual or Semi-Annual

semi-annual shareholder report

Additional Information [Text Block]

You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.

Additional Information Phone Number

1-800-345-2021

Additional Information Website

americancentury.com/docs

Expenses [Text Block]


What were the fund costs for the last six months? (based on a hypothetical $10,000 investment)

	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
A Class	$36	0.71%

Expenses Paid, Amount

$ 36

Expense Ratio, Percent

0.71%

Net Assets

$ 2,221,727,663

Holdings Count | holding

1,052

Advisory Fees Paid, Amount

$ 3,234,198

Investment Company, Portfolio Turnover

15.00%

Holdings [Text Block]


Fund Holdings


			Types of Investments in Portfolio (as a % of net assets)
			Municipal Securities			100.8%
			Affiliated Funds			0.5%
			Other Assets and Liabilities			(1.3)%

C000087987 [Member]

Shareholder Report [Line Items]

Fund Name

California Intermediate-Term Tax-Free Bond Fund

Class Name

C Class

Trading Symbol

BCIYX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about California Intermediate-Term Tax-Free Bond Fund for the period of September 1, 2025 to February 28, 2026.

Shareholder Report Annual or Semi-Annual

semi-annual shareholder report

Additional Information [Text Block]

You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.

Additional Information Phone Number

1-800-345-2021

Additional Information Website

americancentury.com/docs

Expenses [Text Block]


What were the fund costs for the last six months? (based on a hypothetical $10,000 investment)

	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
C Class	$74	1.46%

Expenses Paid, Amount

$ 74

Expense Ratio, Percent

1.46%

Net Assets

$ 2,221,727,663

Holdings Count | holding

1,052

Advisory Fees Paid, Amount

$ 3,234,198

Investment Company, Portfolio Turnover

15.00%

Holdings [Text Block]


Fund Holdings


			Types of Investments in Portfolio (as a % of net assets)
			Municipal Securities			100.8%
			Affiliated Funds			0.5%
			Other Assets and Liabilities			(1.3)%

C000015528 [Member]

Shareholder Report [Line Items]

Fund Name

California Tax-Free Money Market Fund

Class Name

Investor Class

Trading Symbol

BCTXX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about California Tax-Free Money Market Fund for the period of September 1, 2025 to February 28, 2026.

Shareholder Report Annual or Semi-Annual

semi-annual shareholder report

Additional Information [Text Block]

You can find additional information about the fund at americancentury.com/docs. You can also request this information by contacting us at 1-800-345-2021.

Additional Information Phone Number

1-800-345-2021

Additional Information Website

americancentury.com/docs

Expenses [Text Block]


What were the fund costs for the last six months? (based on a hypothetical $10,000 investment)

	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Investor Class	$24	0.49%

Expenses Paid, Amount

$ 24

Expense Ratio, Percent

0.49%

Net Assets

$ 113,408,866

Holdings Count | holding

Advisory Fees Paid, Amount

$ 271,138

Additional Fund Statistics [Text Block]


Fund Statistics
Net Assets	$113,408,866
Management Fees (dollars paid during the reporting period)	$271,138

Total Number of Portfolio Holdings	65
7-Day Current Yield - Investor Class	1.49	%
7-Day Effective Yield - Investor Class	1.50	%

Holdings [Text Block]


Fund Holdings


			Types of Investments in Portfolio (as a % of net assets)
			Municipal Securities			100.1%
			Other Assets and Liabilities			(0.1)%