Label

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[RiskReturnAbstract]

rr_RiskReturnAbstract

Document Type

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Other

Document Period End Date

dei_DocumentPeriodEndDate

May 02, 2013

Registrant Name

dei_EntityRegistrantName

AMERICAN CENTURY ASSET ALLOCATION PORTFOLIOS, INC.

Central Index Key

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0001293210

Amendment Flag

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false

Trading Symbol

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acaap

Document Creation Date

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May 02, 2013

Document Effective Date

dei_DocumentEffectiveDate

Dec. 01, 2012

Prospectus Date

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Dec. 01, 2012

LIVESTRONG INCOME PORTFOLIO

[RiskReturnAbstract]

rr_RiskReturnAbstract

[SupplementTextBlock]

acaap_SupplementTextBlock

American Century Asset Allocation Portfolios, Inc. 

Summary Prospectuses and Prospectus Supplement

LIVESTRONG® Income Portfolio ■ LIVESTRONG® 2015 Portfolio

LIVESTRONG® 2020 Portfolio ■ LIVESTRONG® 2025 Portfolio

LIVESTRONG® 2030 Portfolio ■ LIVESTRONG® 2035 Portfolio

LIVESTRONG® 2040 Portfolio ■ LIVESTRONG® 2045 Portfolio

LIVESTRONG® 2050 Portfolio ■ LIVESTRONG® 2055 Portfolio

Supplement dated May 2, 2013■ Summary Prospectuses and Prospectus dated December 1, 2012

Effective May 31, 2013, the names of the LIVESTRONG Portfolios will be changed to the following:

LIVESTRONG® Income Portfolio	One ChoiceSM In Retirement Portfolio
LIVESTRONG® 2015 Portfolio	One ChoiceSM 2015 Portfolio
LIVESTRONG® 2020 Portfolio	One ChoiceSM 2020 Portfolio
LIVESTRONG® 2025 Portfolio	One ChoiceSM 2025 Portfolio
LIVESTRONG® 2030 Portfolio	One ChoiceSM 2030 Portfolio
LIVESTRONG® 2035 Portfolio	One ChoiceSM 2035 Portfolio
LIVESTRONG® 2040 Portfolio	One ChoiceSM 2040 Portfolio
LIVESTRONG® 2045 Portfolio	One ChoiceSM 2045 Portfolio
LIVESTRONG® 2050 Portfolio	One ChoiceSM 2050 Portfolio
LIVESTRONG® 2055 Portfolio	One ChoiceSM 2055 Portfolio

LIVESTRONG 2015 PORTFOLIO

[RiskReturnAbstract]

rr_RiskReturnAbstract

[SupplementTextBlock]

acaap_SupplementTextBlock

American Century Asset Allocation Portfolios, Inc. 

Summary Prospectuses and Prospectus Supplement

LIVESTRONG® Income Portfolio ■ LIVESTRONG® 2015 Portfolio

LIVESTRONG® 2020 Portfolio ■ LIVESTRONG® 2025 Portfolio

LIVESTRONG® 2030 Portfolio ■ LIVESTRONG® 2035 Portfolio

LIVESTRONG® 2040 Portfolio ■ LIVESTRONG® 2045 Portfolio

LIVESTRONG® 2050 Portfolio ■ LIVESTRONG® 2055 Portfolio

Supplement dated May 2, 2013■ Summary Prospectuses and Prospectus dated December 1, 2012

Effective May 31, 2013, the names of the LIVESTRONG Portfolios will be changed to the following:

LIVESTRONG® Income Portfolio	One ChoiceSM In Retirement Portfolio
LIVESTRONG® 2015 Portfolio	One ChoiceSM 2015 Portfolio
LIVESTRONG® 2020 Portfolio	One ChoiceSM 2020 Portfolio
LIVESTRONG® 2025 Portfolio	One ChoiceSM 2025 Portfolio
LIVESTRONG® 2030 Portfolio	One ChoiceSM 2030 Portfolio
LIVESTRONG® 2035 Portfolio	One ChoiceSM 2035 Portfolio
LIVESTRONG® 2040 Portfolio	One ChoiceSM 2040 Portfolio
LIVESTRONG® 2045 Portfolio	One ChoiceSM 2045 Portfolio
LIVESTRONG® 2050 Portfolio	One ChoiceSM 2050 Portfolio
LIVESTRONG® 2055 Portfolio	One ChoiceSM 2055 Portfolio

LIVESTRONG 2020 PORTFOLIO

[RiskReturnAbstract]

rr_RiskReturnAbstract

[SupplementTextBlock]

acaap_SupplementTextBlock

American Century Asset Allocation Portfolios, Inc. 

Summary Prospectuses and Prospectus Supplement

LIVESTRONG® Income Portfolio ■ LIVESTRONG® 2015 Portfolio

LIVESTRONG® 2020 Portfolio ■ LIVESTRONG® 2025 Portfolio

LIVESTRONG® 2030 Portfolio ■ LIVESTRONG® 2035 Portfolio

LIVESTRONG® 2040 Portfolio ■ LIVESTRONG® 2045 Portfolio

LIVESTRONG® 2050 Portfolio ■ LIVESTRONG® 2055 Portfolio

Supplement dated May 2, 2013■ Summary Prospectuses and Prospectus dated December 1, 2012

Effective May 31, 2013, the names of the LIVESTRONG Portfolios will be changed to the following:

LIVESTRONG® Income Portfolio	One ChoiceSM In Retirement Portfolio
LIVESTRONG® 2015 Portfolio	One ChoiceSM 2015 Portfolio
LIVESTRONG® 2020 Portfolio	One ChoiceSM 2020 Portfolio
LIVESTRONG® 2025 Portfolio	One ChoiceSM 2025 Portfolio
LIVESTRONG® 2030 Portfolio	One ChoiceSM 2030 Portfolio
LIVESTRONG® 2035 Portfolio	One ChoiceSM 2035 Portfolio
LIVESTRONG® 2040 Portfolio	One ChoiceSM 2040 Portfolio
LIVESTRONG® 2045 Portfolio	One ChoiceSM 2045 Portfolio
LIVESTRONG® 2050 Portfolio	One ChoiceSM 2050 Portfolio
LIVESTRONG® 2055 Portfolio	One ChoiceSM 2055 Portfolio

LIVESTRONG 2025 PORTFOLIO

[RiskReturnAbstract]

rr_RiskReturnAbstract

[SupplementTextBlock]

acaap_SupplementTextBlock

American Century Asset Allocation Portfolios, Inc. 

Summary Prospectuses and Prospectus Supplement

LIVESTRONG® Income Portfolio ■ LIVESTRONG® 2015 Portfolio

LIVESTRONG® 2020 Portfolio ■ LIVESTRONG® 2025 Portfolio

LIVESTRONG® 2030 Portfolio ■ LIVESTRONG® 2035 Portfolio

LIVESTRONG® 2040 Portfolio ■ LIVESTRONG® 2045 Portfolio

LIVESTRONG® 2050 Portfolio ■ LIVESTRONG® 2055 Portfolio

Supplement dated May 2, 2013■ Summary Prospectuses and Prospectus dated December 1, 2012

Effective May 31, 2013, the names of the LIVESTRONG Portfolios will be changed to the following:

LIVESTRONG® Income Portfolio	One ChoiceSM In Retirement Portfolio
LIVESTRONG® 2015 Portfolio	One ChoiceSM 2015 Portfolio
LIVESTRONG® 2020 Portfolio	One ChoiceSM 2020 Portfolio
LIVESTRONG® 2025 Portfolio	One ChoiceSM 2025 Portfolio
LIVESTRONG® 2030 Portfolio	One ChoiceSM 2030 Portfolio
LIVESTRONG® 2035 Portfolio	One ChoiceSM 2035 Portfolio
LIVESTRONG® 2040 Portfolio	One ChoiceSM 2040 Portfolio
LIVESTRONG® 2045 Portfolio	One ChoiceSM 2045 Portfolio
LIVESTRONG® 2050 Portfolio	One ChoiceSM 2050 Portfolio
LIVESTRONG® 2055 Portfolio	One ChoiceSM 2055 Portfolio

LIVESTRONG 2030 PORTFOLIO

[RiskReturnAbstract]

rr_RiskReturnAbstract

[SupplementTextBlock]

acaap_SupplementTextBlock

American Century Asset Allocation Portfolios, Inc. 

Summary Prospectuses and Prospectus Supplement

LIVESTRONG® Income Portfolio ■ LIVESTRONG® 2015 Portfolio

LIVESTRONG® 2020 Portfolio ■ LIVESTRONG® 2025 Portfolio

LIVESTRONG® 2030 Portfolio ■ LIVESTRONG® 2035 Portfolio

LIVESTRONG® 2040 Portfolio ■ LIVESTRONG® 2045 Portfolio

LIVESTRONG® 2050 Portfolio ■ LIVESTRONG® 2055 Portfolio

Supplement dated May 2, 2013■ Summary Prospectuses and Prospectus dated December 1, 2012

Effective May 31, 2013, the names of the LIVESTRONG Portfolios will be changed to the following:

LIVESTRONG® Income Portfolio	One ChoiceSM In Retirement Portfolio
LIVESTRONG® 2015 Portfolio	One ChoiceSM 2015 Portfolio
LIVESTRONG® 2020 Portfolio	One ChoiceSM 2020 Portfolio
LIVESTRONG® 2025 Portfolio	One ChoiceSM 2025 Portfolio
LIVESTRONG® 2030 Portfolio	One ChoiceSM 2030 Portfolio
LIVESTRONG® 2035 Portfolio	One ChoiceSM 2035 Portfolio
LIVESTRONG® 2040 Portfolio	One ChoiceSM 2040 Portfolio
LIVESTRONG® 2045 Portfolio	One ChoiceSM 2045 Portfolio
LIVESTRONG® 2050 Portfolio	One ChoiceSM 2050 Portfolio
LIVESTRONG® 2055 Portfolio	One ChoiceSM 2055 Portfolio

LIVESTRONG 2035 PORTFOLIO

[RiskReturnAbstract]

rr_RiskReturnAbstract

[SupplementTextBlock]

acaap_SupplementTextBlock

American Century Asset Allocation Portfolios, Inc. 

Summary Prospectuses and Prospectus Supplement

LIVESTRONG® Income Portfolio ■ LIVESTRONG® 2015 Portfolio

LIVESTRONG® 2020 Portfolio ■ LIVESTRONG® 2025 Portfolio

LIVESTRONG® 2030 Portfolio ■ LIVESTRONG® 2035 Portfolio

LIVESTRONG® 2040 Portfolio ■ LIVESTRONG® 2045 Portfolio

LIVESTRONG® 2050 Portfolio ■ LIVESTRONG® 2055 Portfolio

Supplement dated May 2, 2013■ Summary Prospectuses and Prospectus dated December 1, 2012

Effective May 31, 2013, the names of the LIVESTRONG Portfolios will be changed to the following:

LIVESTRONG® Income Portfolio	One ChoiceSM In Retirement Portfolio
LIVESTRONG® 2015 Portfolio	One ChoiceSM 2015 Portfolio
LIVESTRONG® 2020 Portfolio	One ChoiceSM 2020 Portfolio
LIVESTRONG® 2025 Portfolio	One ChoiceSM 2025 Portfolio
LIVESTRONG® 2030 Portfolio	One ChoiceSM 2030 Portfolio
LIVESTRONG® 2035 Portfolio	One ChoiceSM 2035 Portfolio
LIVESTRONG® 2040 Portfolio	One ChoiceSM 2040 Portfolio
LIVESTRONG® 2045 Portfolio	One ChoiceSM 2045 Portfolio
LIVESTRONG® 2050 Portfolio	One ChoiceSM 2050 Portfolio
LIVESTRONG® 2055 Portfolio	One ChoiceSM 2055 Portfolio

LIVESTRONG 2040 PORTFOLIO

[RiskReturnAbstract]

rr_RiskReturnAbstract

[SupplementTextBlock]

acaap_SupplementTextBlock

American Century Asset Allocation Portfolios, Inc. 

Summary Prospectuses and Prospectus Supplement

LIVESTRONG® Income Portfolio ■ LIVESTRONG® 2015 Portfolio

LIVESTRONG® 2020 Portfolio ■ LIVESTRONG® 2025 Portfolio

LIVESTRONG® 2030 Portfolio ■ LIVESTRONG® 2035 Portfolio

LIVESTRONG® 2040 Portfolio ■ LIVESTRONG® 2045 Portfolio

LIVESTRONG® 2050 Portfolio ■ LIVESTRONG® 2055 Portfolio

Supplement dated May 2, 2013■ Summary Prospectuses and Prospectus dated December 1, 2012

Effective May 31, 2013, the names of the LIVESTRONG Portfolios will be changed to the following:

LIVESTRONG® Income Portfolio	One ChoiceSM In Retirement Portfolio
LIVESTRONG® 2015 Portfolio	One ChoiceSM 2015 Portfolio
LIVESTRONG® 2020 Portfolio	One ChoiceSM 2020 Portfolio
LIVESTRONG® 2025 Portfolio	One ChoiceSM 2025 Portfolio
LIVESTRONG® 2030 Portfolio	One ChoiceSM 2030 Portfolio
LIVESTRONG® 2035 Portfolio	One ChoiceSM 2035 Portfolio
LIVESTRONG® 2040 Portfolio	One ChoiceSM 2040 Portfolio
LIVESTRONG® 2045 Portfolio	One ChoiceSM 2045 Portfolio
LIVESTRONG® 2050 Portfolio	One ChoiceSM 2050 Portfolio
LIVESTRONG® 2055 Portfolio	One ChoiceSM 2055 Portfolio

LIVESTRONG 2045 PORTFOLIO

[RiskReturnAbstract]

rr_RiskReturnAbstract

[SupplementTextBlock]

acaap_SupplementTextBlock

American Century Asset Allocation Portfolios, Inc. 

Summary Prospectuses and Prospectus Supplement

LIVESTRONG® Income Portfolio ■ LIVESTRONG® 2015 Portfolio

LIVESTRONG® 2020 Portfolio ■ LIVESTRONG® 2025 Portfolio

LIVESTRONG® 2030 Portfolio ■ LIVESTRONG® 2035 Portfolio

LIVESTRONG® 2040 Portfolio ■ LIVESTRONG® 2045 Portfolio

LIVESTRONG® 2050 Portfolio ■ LIVESTRONG® 2055 Portfolio

Supplement dated May 2, 2013■ Summary Prospectuses and Prospectus dated December 1, 2012

Effective May 31, 2013, the names of the LIVESTRONG Portfolios will be changed to the following:

LIVESTRONG® Income Portfolio	One ChoiceSM In Retirement Portfolio
LIVESTRONG® 2015 Portfolio	One ChoiceSM 2015 Portfolio
LIVESTRONG® 2020 Portfolio	One ChoiceSM 2020 Portfolio
LIVESTRONG® 2025 Portfolio	One ChoiceSM 2025 Portfolio
LIVESTRONG® 2030 Portfolio	One ChoiceSM 2030 Portfolio
LIVESTRONG® 2035 Portfolio	One ChoiceSM 2035 Portfolio
LIVESTRONG® 2040 Portfolio	One ChoiceSM 2040 Portfolio
LIVESTRONG® 2045 Portfolio	One ChoiceSM 2045 Portfolio
LIVESTRONG® 2050 Portfolio	One ChoiceSM 2050 Portfolio
LIVESTRONG® 2055 Portfolio	One ChoiceSM 2055 Portfolio

LIVESTRONG 2050 PORTFOLIO

[RiskReturnAbstract]

rr_RiskReturnAbstract

[SupplementTextBlock]

acaap_SupplementTextBlock

American Century Asset Allocation Portfolios, Inc. 

Summary Prospectuses and Prospectus Supplement

LIVESTRONG® Income Portfolio ■ LIVESTRONG® 2015 Portfolio

LIVESTRONG® 2020 Portfolio ■ LIVESTRONG® 2025 Portfolio

LIVESTRONG® 2030 Portfolio ■ LIVESTRONG® 2035 Portfolio

LIVESTRONG® 2040 Portfolio ■ LIVESTRONG® 2045 Portfolio

LIVESTRONG® 2050 Portfolio ■ LIVESTRONG® 2055 Portfolio

Supplement dated May 2, 2013■ Summary Prospectuses and Prospectus dated December 1, 2012

Effective May 31, 2013, the names of the LIVESTRONG Portfolios will be changed to the following:

LIVESTRONG® Income Portfolio	One ChoiceSM In Retirement Portfolio
LIVESTRONG® 2015 Portfolio	One ChoiceSM 2015 Portfolio
LIVESTRONG® 2020 Portfolio	One ChoiceSM 2020 Portfolio
LIVESTRONG® 2025 Portfolio	One ChoiceSM 2025 Portfolio
LIVESTRONG® 2030 Portfolio	One ChoiceSM 2030 Portfolio
LIVESTRONG® 2035 Portfolio	One ChoiceSM 2035 Portfolio
LIVESTRONG® 2040 Portfolio	One ChoiceSM 2040 Portfolio
LIVESTRONG® 2045 Portfolio	One ChoiceSM 2045 Portfolio
LIVESTRONG® 2050 Portfolio	One ChoiceSM 2050 Portfolio
LIVESTRONG® 2055 Portfolio	One ChoiceSM 2055 Portfolio

LIVESTRONG 2055 PORTFOLIO

[RiskReturnAbstract]

rr_RiskReturnAbstract

[SupplementTextBlock]

acaap_SupplementTextBlock

American Century Asset Allocation Portfolios, Inc. 

Summary Prospectuses and Prospectus Supplement

LIVESTRONG® Income Portfolio ■ LIVESTRONG® 2015 Portfolio

LIVESTRONG® 2020 Portfolio ■ LIVESTRONG® 2025 Portfolio

LIVESTRONG® 2030 Portfolio ■ LIVESTRONG® 2035 Portfolio

LIVESTRONG® 2040 Portfolio ■ LIVESTRONG® 2045 Portfolio

LIVESTRONG® 2050 Portfolio ■ LIVESTRONG® 2055 Portfolio

Supplement dated May 2, 2013■ Summary Prospectuses and Prospectus dated December 1, 2012

Effective May 31, 2013, the names of the LIVESTRONG Portfolios will be changed to the following:

LIVESTRONG® Income Portfolio	One ChoiceSM In Retirement Portfolio
LIVESTRONG® 2015 Portfolio	One ChoiceSM 2015 Portfolio
LIVESTRONG® 2020 Portfolio	One ChoiceSM 2020 Portfolio
LIVESTRONG® 2025 Portfolio	One ChoiceSM 2025 Portfolio
LIVESTRONG® 2030 Portfolio	One ChoiceSM 2030 Portfolio
LIVESTRONG® 2035 Portfolio	One ChoiceSM 2035 Portfolio
LIVESTRONG® 2040 Portfolio	One ChoiceSM 2040 Portfolio
LIVESTRONG® 2045 Portfolio	One ChoiceSM 2045 Portfolio
LIVESTRONG® 2050 Portfolio	One ChoiceSM 2050 Portfolio
LIVESTRONG® 2055 Portfolio	One ChoiceSM 2055 Portfolio