| Shareholder Report | 12 Months Ended | 88 Months Ended |
| Jul. 31, 2024 USD ($) holding | Jul. 31, 2024 USD ($) holding |
| Shareholder Report [Line Items] | | |
| Document Type | N-CSR | |
| Amendment Flag | false | |
| Registrant Name | AMERICAN CENTURY STRATEGIC ASSET ALLOCATIONS, INC. | |
| Entity Central Index Key | 0000924211 | |
| Entity Investment Company Type | N-1A | |
| Document Period End Date | Jul. 31, 2024 | |
| C000016319 [Member] | | |
| Shareholder Report [Line Items] | | |
| Fund Name | Strategic Allocation: Aggressive Fund | |
| Class Name | Investor Class | |
| Trading Symbol | TWSAX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Strategic Allocation: Aggressive Fund for the period of August 1, 2023 to July 31, 2024. | |
| Shareholder Report Annual or Semi-Annual | 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 year? (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 $66 0.62% | |
| Expenses Paid, Amount | $ 66 | |
| Expense Ratio, Percent | 0.62% | |
| Factors Affecting Performance [Text Block] | What were the key factors that affected the fund’s performance? Strategic Allocation: Aggressive Fund Investor Class returned 12.93% for the reporting period ended July 31, 2024. The fund is an asset allocation fund. That is, it diversifies its assets among various classes of investments such as equity securities, bonds and money market instruments. The fund seeks the highest level of total return consistent with its asset mix. See the Fund Holdings for the portfolio's asset weights. Below, we discuss the factors that affected these asset classes. • Investments in domestic equity holdings contributed meaningfully to performance. U.S. stocks did very well from late 2023 through mid-2024 as a much-anticipated recession failed to arrive. Investors favored stocks benefiting from heavy investment in artificial intelligence-related chips and technologies. Stocks gave back some gains in July, however, amid worries about slowing economic conditions. • The portfolio's non-U.S. equity holdings also rose but by a smaller amount than U.S. large-cap stocks. Signs of slowing economic growth led the European Central Bank to lower short-term interest rates for the first time in almost five years in June 2024. Emerging markets equities generally fared better as Taiwanese and South Korean companies benefited from strength in technology stocks. • The portfolio's domestic fixed-income holdings contributed to performance. Bond yields were volatile amid changing perceptions of the economy and inflation. The benchmark 10-year Treasury yield started and ended the period at around 4% but went as high as 5% and as low as 3.8%. Reflecting the rally in stocks and strength in corporate earnings, corporate bonds did very well. | |
| Line Graph [Table Text Block] | Cumulative Performance (based on an initial $10,000 investment) July 31, 2014, through July 31, 2024 | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns 1 Year 5 Year 10 Year Investor Class 12.93% 9.18% 8.00% Russell 3000 21.07% 14.23% 12.58% Bloomberg U.S. Aggregate 5.10% 0.19% 1.61% S&P 500 22.15% 15.00% 13.15% Bloomberg U.S. 1-3 Month Treasury Bill 5.51% 2.22% 1.54% | |
| No Deduction of Taxes [Text Block] | The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. | |
| Updated Performance Information Location [Text Block] | Visit americancentury.com for more recent performance information. | |
| Net Assets | $ 662,512,290 | $ 662,512,290 |
| Holdings Count | holding | 814 | 814 |
| Advisory Fees Paid, Amount | $ 3,185,115 | |
| Investment Company, Portfolio Turnover | 29% | |
| Holdings [Text Block] | Fund Holdings Types of Investments in Portfolio (as a % of net assets) Affiliated Funds 52.6% Common Stocks 30.9% U.S. Treasury Securities 8.6% Corporate Bonds 1.3% Sovereign Governments and Agencies 1.2% Collateralized Loan Obligations 0.2% Preferred Stocks 0.2% Asset-Backed Securities 0.1% Municipal Securities 0.0% Collateralized Mortgage Obligations 0.0% U.S. Government Agency Mortgage-Backed Securities 0.0% Exchange-Traded Funds 0.0% Short-Term Investments 7.3% Other Assets and Liabilities (2.4)% | |
| C000016321 [Member] | | |
| Shareholder Report [Line Items] | | |
| Fund Name | Strategic Allocation: Aggressive Fund | |
| Class Name | I Class | |
| Trading Symbol | AAAIX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Strategic Allocation: Aggressive Fund for the period of August 1, 2023 to July 31, 2024. | |
| Shareholder Report Annual or Semi-Annual | 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 year? (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 $45 0.42% | |
| Expenses Paid, Amount | $ 45 | |
| Expense Ratio, Percent | 0.42% | |
| Factors Affecting Performance [Text Block] | What were the key factors that affected the fund’s performance? Strategic Allocation: Aggressive Fund I Class returned 13.16% for the reporting period ended July 31, 2024. The fund is an asset allocation fund. That is, it diversifies its assets among various classes of investments such as equity securities, bonds and money market instruments. The fund seeks the highest level of total return consistent with its asset mix. See the Fund Holdings for the portfolio's asset weights. Below, we discuss the factors that affected these asset classes. • Investments in domestic equity holdings contributed meaningfully to performance. U.S. stocks did very well from late 2023 through mid-2024 as a much-anticipated recession failed to arrive. Investors favored stocks benefiting from heavy investment in artificial intelligence-related chips and technologies. Stocks gave back some gains in July, however, amid worries about slowing economic conditions. • The portfolio's non-U.S. equity holdings also rose but by a smaller amount than U.S. large-cap stocks. Signs of slowing economic growth led the European Central Bank to lower short-term interest rates for the first time in almost five years in June 2024. Emerging markets equities generally fared better as Taiwanese and South Korean companies benefited from strength in technology stocks. • The portfolio's domestic fixed-income holdings contributed to performance. Bond yields were volatile amid changing perceptions of the economy and inflation. The benchmark 10-year Treasury yield started and ended the period at around 4% but went as high as 5% and as low as 3.8%. Reflecting the rally in stocks and strength in corporate earnings, corporate bonds did very well. | |
| Line Graph [Table Text Block] | Cumulative Performance (based on an initial $10,000 investment) July 31, 2014, through July 31, 2024 | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns 1 Year 5 Year 10 Year I Class 13.16% 9.38% 8.20% Russell 3000 21.07% 14.23% 12.58% Bloomberg U.S. Aggregate 5.10% 0.19% 1.61% S&P 500 22.15% 15.00% 13.15% Bloomberg U.S. 1-3 Month Treasury Bill 5.51% 2.22% 1.54% | |
| No Deduction of Taxes [Text Block] | The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. | |
| Updated Performance Information Location [Text Block] | Visit americancentury.com for more recent performance information. | |
| Net Assets | $ 662,512,290 | $ 662,512,290 |
| Holdings Count | holding | 814 | 814 |
| Advisory Fees Paid, Amount | $ 3,185,115 | |
| Investment Company, Portfolio Turnover | 29% | |
| Holdings [Text Block] | Fund Holdings Types of Investments in Portfolio (as a % of net assets) Affiliated Funds 52.6% Common Stocks 30.9% U.S. Treasury Securities 8.6% Corporate Bonds 1.3% Sovereign Governments and Agencies 1.2% Collateralized Loan Obligations 0.2% Preferred Stocks 0.2% Asset-Backed Securities 0.1% Municipal Securities 0.0% Collateralized Mortgage Obligations 0.0% U.S. Government Agency Mortgage-Backed Securities 0.0% Exchange-Traded Funds 0.0% Short-Term Investments 7.3% Other Assets and Liabilities (2.4)% | |
| C000016320 [Member] | | |
| Shareholder Report [Line Items] | | |
| Fund Name | Strategic Allocation: Aggressive Fund | |
| Class Name | A Class | |
| Trading Symbol | ACVAX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Strategic Allocation: Aggressive Fund for the period of August 1, 2023 to July 31, 2024. | |
| Shareholder Report Annual or Semi-Annual | 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 year? (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 $92 0.87% | |
| Expenses Paid, Amount | $ 92 | |
| Expense Ratio, Percent | 0.87% | |
| Factors Affecting Performance [Text Block] | What were the key factors that affected the fund’s performance? Strategic Allocation: Aggressive Fund A Class returned 12.63% for the reporting period ended July 31, 2024. The fund is an asset allocation fund. That is, it diversifies its assets among various classes of investments such as equity securities, bonds and money market instruments. The fund seeks the highest level of total return consistent with its asset mix. See the Fund Holdings for the portfolio's asset weights. Below, we discuss the factors that affected these asset classes. • Investments in domestic equity holdings contributed meaningfully to performance. U.S. stocks did very well from late 2023 through mid-2024 as a much-anticipated recession failed to arrive. Investors favored stocks benefiting from heavy investment in artificial intelligence-related chips and technologies. Stocks gave back some gains in July, however, amid worries about slowing economic conditions. • The portfolio's non-U.S. equity holdings also rose but by a smaller amount than U.S. large-cap stocks. Signs of slowing economic growth led the European Central Bank to lower short-term interest rates for the first time in almost five years in June 2024. Emerging markets equities generally fared better as Taiwanese and South Korean companies benefited from strength in technology stocks. • The portfolio's domestic fixed-income holdings contributed to performance. Bond yields were volatile amid changing perceptions of the economy and inflation. The benchmark 10-year Treasury yield started and ended the period at around 4% but went as high as 5% and as low as 3.8%. Reflecting the rally in stocks and strength in corporate earnings, corporate bonds did very well. | |
| Line Graph [Table Text Block] | Cumulative Performance (based on an initial $10,000 investment) July 31, 2014, through July 31, 2024 The initial investment is adjusted to reflect the maximum initial sales charge. | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns 1 Year 5 Year 10 Year A Class 12.63% 8.91% 7.72% A Class - with sales charge 6.15% 7.63% 7.09% Russell 3000 21.07% 14.23% 12.58% Bloomberg U.S. Aggregate 5.10% 0.19% 1.61% S&P 500 22.15% 15.00% 13.15% Bloomberg U.S. 1-3 Month Treasury Bill 5.51% 2.22% 1.54% | |
| No Deduction of Taxes [Text Block] | The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. | |
| Updated Performance Information Location [Text Block] | Visit americancentury.com for more recent performance information. | |
| Net Assets | $ 662,512,290 | $ 662,512,290 |
| Holdings Count | holding | 814 | 814 |
| Advisory Fees Paid, Amount | $ 3,185,115 | |
| Investment Company, Portfolio Turnover | 29% | |
| Holdings [Text Block] | Fund Holdings Types of Investments in Portfolio (as a % of net assets) Affiliated Funds 52.6% Common Stocks 30.9% U.S. Treasury Securities 8.6% Corporate Bonds 1.3% Sovereign Governments and Agencies 1.2% Collateralized Loan Obligations 0.2% Preferred Stocks 0.2% Asset-Backed Securities 0.1% Municipal Securities 0.0% Collateralized Mortgage Obligations 0.0% U.S. Government Agency Mortgage-Backed Securities 0.0% Exchange-Traded Funds 0.0% Short-Term Investments 7.3% Other Assets and Liabilities (2.4)% | |
| C000016324 [Member] | | |
| Shareholder Report [Line Items] | | |
| Fund Name | Strategic Allocation: Aggressive Fund | |
| Class Name | C Class | |
| Trading Symbol | ASTAX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Strategic Allocation: Aggressive Fund for the period of August 1, 2023 to July 31, 2024. | |
| Shareholder Report Annual or Semi-Annual | 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 year? (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 $172 1.62% | |
| Expenses Paid, Amount | $ 172 | |
| Expense Ratio, Percent | 1.62% | |
| Factors Affecting Performance [Text Block] | What were the key factors that affected the fund’s performance? Strategic Allocation: Aggressive Fund C Class returned 11.73% for the reporting period ended July 31, 2024. The fund is an asset allocation fund. That is, it diversifies its assets among various classes of investments such as equity securities, bonds and money market instruments. The fund seeks the highest level of total return consistent with its asset mix. See the Fund Holdings for the portfolio's asset weights. Below, we discuss the factors that affected these asset classes. • Investments in domestic equity holdings contributed meaningfully to performance. U.S. stocks did very well from late 2023 through mid-2024 as a much-anticipated recession failed to arrive. Investors favored stocks benefiting from heavy investment in artificial intelligence-related chips and technologies. Stocks gave back some gains in July, however, amid worries about slowing economic conditions. • The portfolio's non-U.S. equity holdings also rose but by a smaller amount than U.S. large-cap stocks. Signs of slowing economic growth led the European Central Bank to lower short-term interest rates for the first time in almost five years in June 2024. Emerging markets equities generally fared better as Taiwanese and South Korean companies benefited from strength in technology stocks. • The portfolio's domestic fixed-income holdings contributed to performance. Bond yields were volatile amid changing perceptions of the economy and inflation. The benchmark 10-year Treasury yield started and ended the period at around 4% but went as high as 5% and as low as 3.8%. Reflecting the rally in stocks and strength in corporate earnings, corporate bonds did very well. | |
| Line Graph [Table Text Block] | Cumulative Performance (based on an initial $10,000 investment) July 31, 2014, through July 31, 2024 | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns 1 Year 5 Year 10 Year C Class 11.73% 8.10% 6.92% Russell 3000 21.07% 14.23% 12.58% Bloomberg U.S. Aggregate 5.10% 0.19% 1.61% S&P 500 22.15% 15.00% 13.15% Bloomberg U.S. 1-3 Month Treasury Bill 5.51% 2.22% 1.54% | |
| No Deduction of Taxes [Text Block] | The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. | |
| Updated Performance Information Location [Text Block] | Visit americancentury.com for more recent performance information. | |
| Net Assets | $ 662,512,290 | $ 662,512,290 |
| Holdings Count | holding | 814 | 814 |
| Advisory Fees Paid, Amount | $ 3,185,115 | |
| Investment Company, Portfolio Turnover | 29% | |
| Holdings [Text Block] | Fund Holdings Types of Investments in Portfolio (as a % of net assets) Affiliated Funds 52.6% Common Stocks 30.9% U.S. Treasury Securities 8.6% Corporate Bonds 1.3% Sovereign Governments and Agencies 1.2% Collateralized Loan Obligations 0.2% Preferred Stocks 0.2% Asset-Backed Securities 0.1% Municipal Securities 0.0% Collateralized Mortgage Obligations 0.0% U.S. Government Agency Mortgage-Backed Securities 0.0% Exchange-Traded Funds 0.0% Short-Term Investments 7.3% Other Assets and Liabilities (2.4)% | |
| C000016318 [Member] | | |
| Shareholder Report [Line Items] | | |
| Fund Name | Strategic Allocation: Aggressive Fund | |
| Class Name | R Class | |
| Trading Symbol | AAARX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Strategic Allocation: Aggressive Fund for the period of August 1, 2023 to July 31, 2024. | |
| Shareholder Report Annual or Semi-Annual | 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 year? (based on a hypothetical $10,000 investment) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment R Class $119 1.12% | |
| Expenses Paid, Amount | $ 119 | |
| Expense Ratio, Percent | 1.12% | |
| Factors Affecting Performance [Text Block] | What were the key factors that affected the fund’s performance? Strategic Allocation: Aggressive Fund R Class returned 12.38% for the reporting period ended July 31, 2024. The fund is an asset allocation fund. That is, it diversifies its assets among various classes of investments such as equity securities, bonds and money market instruments. The fund seeks the highest level of total return consistent with its asset mix. See the Fund Holdings for the portfolio's asset weights. Below, we discuss the factors that affected these asset classes. • Investments in domestic equity holdings contributed meaningfully to performance. U.S. stocks did very well from late 2023 through mid-2024 as a much-anticipated recession failed to arrive. Investors favored stocks benefiting from heavy investment in artificial intelligence-related chips and technologies. Stocks gave back some gains in July, however, amid worries about slowing economic conditions. • The portfolio's non-U.S. equity holdings also rose but by a smaller amount than U.S. large-cap stocks. Signs of slowing economic growth led the European Central Bank to lower short-term interest rates for the first time in almost five years in June 2024. Emerging markets equities generally fared better as Taiwanese and South Korean companies benefited from strength in technology stocks. • The portfolio's domestic fixed-income holdings contributed to performance. Bond yields were volatile amid changing perceptions of the economy and inflation. The benchmark 10-year Treasury yield started and ended the period at around 4% but went as high as 5% and as low as 3.8%. Reflecting the rally in stocks and strength in corporate earnings, corporate bonds did very well. | |
| Line Graph [Table Text Block] | Cumulative Performance (based on an initial $10,000 investment) July 31, 2014, through July 31, 2024 | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns 1 Year 5 Year 10 Year R Class 12.38% 8.62% 7.45% Russell 3000 21.07% 14.23% 12.58% Bloomberg U.S. Aggregate 5.10% 0.19% 1.61% S&P 500 22.15% 15.00% 13.15% Bloomberg U.S. 1-3 Month Treasury Bill 5.51% 2.22% 1.54% | |
| No Deduction of Taxes [Text Block] | The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. | |
| Updated Performance Information Location [Text Block] | Visit americancentury.com for more recent performance information. | |
| Net Assets | $ 662,512,290 | $ 662,512,290 |
| Holdings Count | holding | 814 | 814 |
| Advisory Fees Paid, Amount | $ 3,185,115 | |
| Investment Company, Portfolio Turnover | 29% | |
| Holdings [Text Block] | Fund Holdings Types of Investments in Portfolio (as a % of net assets) Affiliated Funds 52.6% Common Stocks 30.9% U.S. Treasury Securities 8.6% Corporate Bonds 1.3% Sovereign Governments and Agencies 1.2% Collateralized Loan Obligations 0.2% Preferred Stocks 0.2% Asset-Backed Securities 0.1% Municipal Securities 0.0% Collateralized Mortgage Obligations 0.0% U.S. Government Agency Mortgage-Backed Securities 0.0% Exchange-Traded Funds 0.0% Short-Term Investments 7.3% Other Assets and Liabilities (2.4)% | |
| C000189654 [Member] | | |
| Shareholder Report [Line Items] | | |
| Fund Name | Strategic Allocation: Aggressive Fund | |
| Class Name | R5 Class | |
| Trading Symbol | ASAUX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Strategic Allocation: Aggressive Fund for the period of August 1, 2023 to July 31, 2024. | |
| Shareholder Report Annual or Semi-Annual | 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 year? (based on a hypothetical $10,000 investment) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment R5 Class $45 0.42% | |
| Expenses Paid, Amount | $ 45 | |
| Expense Ratio, Percent | 0.42% | |
| Factors Affecting Performance [Text Block] | What were the key factors that affected the fund’s performance? Strategic Allocation: Aggressive Fund R5 Class returned 13.14% for the reporting period ended July 31, 2024. The fund is an asset allocation fund. That is, it diversifies its assets among various classes of investments such as equity securities, bonds and money market instruments. The fund seeks the highest level of total return consistent with its asset mix. See the Fund Holdings for the portfolio's asset weights. Below, we discuss the factors that affected these asset classes. • Investments in domestic equity holdings contributed meaningfully to performance. U.S. stocks did very well from late 2023 through mid-2024 as a much-anticipated recession failed to arrive. Investors favored stocks benefiting from heavy investment in artificial intelligence-related chips and technologies. Stocks gave back some gains in July, however, amid worries about slowing economic conditions. • The portfolio's non-U.S. equity holdings also rose but by a smaller amount than U.S. large-cap stocks. Signs of slowing economic growth led the European Central Bank to lower short-term interest rates for the first time in almost five years in June 2024. Emerging markets equities generally fared better as Taiwanese and South Korean companies benefited from strength in technology stocks. • The portfolio's domestic fixed-income holdings contributed to performance. Bond yields were volatile amid changing perceptions of the economy and inflation. The benchmark 10-year Treasury yield started and ended the period at around 4% but went as high as 5% and as low as 3.8%. Reflecting the rally in stocks and strength in corporate earnings, corporate bonds did very well. | |
| Line Graph [Table Text Block] | Cumulative Performance (based on an initial $10,000 investment) April 10, 2017, through July 31, 2024 | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns 1 Year 5 Year Since Inception Inception Date R5 Class 13.14% 9.41% 9.18% 4/10/17 Russell 3000 21.07% 14.23% 13.65% — Bloomberg U.S. Aggregate 5.10% 0.19% 1.31% — S&P 500 22.15% 15.00% 14.32% — Bloomberg U.S. 1-3 Month Treasury Bill 5.51% 2.22% 2.06% — | |
| Performance Inception Date | | Apr. 10, 2017 |
| No Deduction of Taxes [Text Block] | The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. | |
| Updated Performance Information Location [Text Block] | Visit americancentury.com for more recent performance information. | |
| Net Assets | $ 662,512,290 | $ 662,512,290 |
| Holdings Count | holding | 814 | 814 |
| Advisory Fees Paid, Amount | $ 3,185,115 | |
| Investment Company, Portfolio Turnover | 29% | |
| Holdings [Text Block] | Fund Holdings Types of Investments in Portfolio (as a % of net assets) Affiliated Funds 52.6% Common Stocks 30.9% U.S. Treasury Securities 8.6% Corporate Bonds 1.3% Sovereign Governments and Agencies 1.2% Collateralized Loan Obligations 0.2% Preferred Stocks 0.2% Asset-Backed Securities 0.1% Municipal Securities 0.0% Collateralized Mortgage Obligations 0.0% U.S. Government Agency Mortgage-Backed Securities 0.0% Exchange-Traded Funds 0.0% Short-Term Investments 7.3% Other Assets and Liabilities (2.4)% | |
| C000131619 [Member] | | |
| Shareholder Report [Line Items] | | |
| Fund Name | Strategic Allocation: Aggressive Fund | |
| Class Name | R6 Class | |
| Trading Symbol | AAAUX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Strategic Allocation: Aggressive Fund for the period of August 1, 2023 to July 31, 2024. | |
| Shareholder Report Annual or Semi-Annual | 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 year? (based on a hypothetical $10,000 investment) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment R6 Class $29 0.27% | |
| Expenses Paid, Amount | $ 29 | |
| Expense Ratio, Percent | 0.27% | |
| Factors Affecting Performance [Text Block] | What were the key factors that affected the fund’s performance? Strategic Allocation: Aggressive Fund R6 Class returned 13.23% for the reporting period ended July 31, 2024. The fund is an asset allocation fund. That is, it diversifies its assets among various classes of investments such as equity securities, bonds and money market instruments. The fund seeks the highest level of total return consistent with its asset mix. See the Fund Holdings for the portfolio's asset weights. Below, we discuss the factors that affected these asset classes. • Investments in domestic equity holdings contributed meaningfully to performance. U.S. stocks did very well from late 2023 through mid-2024 as a much-anticipated recession failed to arrive. Investors favored stocks benefiting from heavy investment in artificial intelligence-related chips and technologies. Stocks gave back some gains in July, however, amid worries about slowing economic conditions. • The portfolio's non-U.S. equity holdings also rose but by a smaller amount than U.S. large-cap stocks. Signs of slowing economic growth led the European Central Bank to lower short-term interest rates for the first time in almost five years in June 2024. Emerging markets equities generally fared better as Taiwanese and South Korean companies benefited from strength in technology stocks. • The portfolio's domestic fixed-income holdings contributed to performance. Bond yields were volatile amid changing perceptions of the economy and inflation. The benchmark 10-year Treasury yield started and ended the period at around 4% but went as high as 5% and as low as 3.8%. Reflecting the rally in stocks and strength in corporate earnings, corporate bonds did very well. | |
| Line Graph [Table Text Block] | Cumulative Performance (based on an initial $10,000 investment) July 31, 2014, through July 31, 2024 | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns 1 Year 5 Year 10 Year R6 Class 13.23% 9.56% 8.37% Russell 3000 21.07% 14.23% 12.58% Bloomberg U.S. Aggregate 5.10% 0.19% 1.61% S&P 500 22.15% 15.00% 13.15% Bloomberg U.S. 1-3 Month Treasury Bill 5.51% 2.22% 1.54% | |
| No Deduction of Taxes [Text Block] | The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. | |
| Updated Performance Information Location [Text Block] | Visit americancentury.com for more recent performance information. | |
| Net Assets | $ 662,512,290 | $ 662,512,290 |
| Holdings Count | holding | 814 | 814 |
| Advisory Fees Paid, Amount | $ 3,185,115 | |
| Investment Company, Portfolio Turnover | 29% | |
| Holdings [Text Block] | Fund Holdings Types of Investments in Portfolio (as a % of net assets) Affiliated Funds 52.6% Common Stocks 30.9% U.S. Treasury Securities 8.6% Corporate Bonds 1.3% Sovereign Governments and Agencies 1.2% Collateralized Loan Obligations 0.2% Preferred Stocks 0.2% Asset-Backed Securities 0.1% Municipal Securities 0.0% Collateralized Mortgage Obligations 0.0% U.S. Government Agency Mortgage-Backed Securities 0.0% Exchange-Traded Funds 0.0% Short-Term Investments 7.3% Other Assets and Liabilities (2.4)% | |
| C000016333 [Member] | | |
| Shareholder Report [Line Items] | | |
| Fund Name | Strategic Allocation: Conservative Fund | |
| Class Name | Investor Class | |
| Trading Symbol | TWSCX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Strategic Allocation: Conservative Fund for the period of August 1, 2023 to July 31, 2024. | |
| Shareholder Report Annual or Semi-Annual | 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 year? (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 $75 0.72% | |
| Expenses Paid, Amount | $ 75 | |
| Expense Ratio, Percent | 0.72% | |
| Factors Affecting Performance [Text Block] | What were the key factors that affected the fund’s performance? Strategic Allocation: Conservative Fund Investor Class returned 9.37% for the reporting period ended July 31, 2024. The fund is an asset allocation fund. That is, it diversifies its assets among various classes of investments such as equity securities, bonds and money market instruments. The fund seeks the highest level of total return consistent with its asset mix. See the Fund Holdings for the portfolio's asset weights. Below, we discuss the factors that affected these asset classes. • Investments in domestic equity holdings contributed meaningfully to performance. U.S. stocks did very well from late 2023 through mid-2024 as a much-anticipated recession failed to arrive. Investors favored stocks benefiting from heavy investment in artificial intelligence-related chips and technologies. Stocks gave back some gains in July, however, amid worries about slowing economic conditions. • The portfolio's non-U.S. equity holdings rose by a smaller amount than U.S. large-cap stocks. The performance disparity can be explained by differences in actual and expected earnings growth—earnings by companies outside the U.S. fell at a faster rate in 2023 and are expected to recover more slowly in 2024 and 2025 than are those of U.S. companies, according to data provider FactSet. • The portfolio's domestic fixed-income holdings contributed to performance. Bond yields were volatile amid changing perceptions of the economy and inflation. The benchmark 10-year Treasury yield started and ended the period at around 4% but went as high as 5% and as low as 3.8%. Reflecting the rally in stocks and strength in corporate earnings, corporate bonds did very well. • Non-U.S. fixed-income holdings produced positive results. Bond prices generally rose and yields fell as manufacturing activity in several developed economies slowed, while inflation concerns eased. That allowed the European Central Bank to cut interest rates. The Bank of Japan, however, raised rates to support its currency and fight imported inflation despite signs of economic weakness. | |
| Line Graph [Table Text Block] | Cumulative Performance (based on an initial $10,000 investment) July 31, 2014, through July 31, 2024 | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns 1 Year 5 Year 10 Year Investor Class 9.37% 5.63% 5.07% Russell 3000 21.07% 14.23% 12.58% Bloomberg U.S. Aggregate 5.10% 0.19% 1.61% S&P 500 22.15% 15.00% 13.15% Bloomberg U.S. 1-3 Month Treasury Bill 5.51% 2.22% 1.54% | |
| No Deduction of Taxes [Text Block] | The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. | |
| Updated Performance Information Location [Text Block] | Visit americancentury.com for more recent performance information. | |
| Net Assets | $ 323,616,822 | $ 323,616,822 |
| Holdings Count | holding | 831 | 831 |
| Advisory Fees Paid, Amount | $ 1,906,662 | |
| Investment Company, Portfolio Turnover | 30% | |
| Holdings [Text Block] | Fund Holdings Types of Investments in Portfolio (as a % of net assets) Affiliated Funds 37.3% U.S. Treasury Securities 23.8% Common Stocks 18.3% Sovereign Governments and Agencies 5.2% Corporate Bonds 2.9% Collateralized Loan Obligations 1.1% Preferred Stocks 0.4% Asset-Backed Securities 0.4% Municipal Securities 0.3% Collateralized Mortgage Obligations 0.2% Exchange-Traded Funds 0.2% U.S. Government Agency Mortgage-Backed Securities 0.1% Short-Term Investments 9.8% Other Assets and Liabilities 0.0% | |
| C000016335 [Member] | | |
| Shareholder Report [Line Items] | | |
| Fund Name | Strategic Allocation: Conservative Fund | |
| Class Name | I Class | |
| Trading Symbol | ACCIX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Strategic Allocation: Conservative Fund for the period of August 1, 2023 to July 31, 2024. | |
| Shareholder Report Annual or Semi-Annual | 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 year? (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 $54 0.52% | |
| Expenses Paid, Amount | $ 54 | |
| Expense Ratio, Percent | 0.52% | |
| Factors Affecting Performance [Text Block] | What were the key factors that affected the fund’s performance? Strategic Allocation: Conservative Fund I Class returned 9.59% for the reporting period ended July 31, 2024. The fund is an asset allocation fund. That is, it diversifies its assets among various classes of investments such as equity securities, bonds and money market instruments. The fund seeks the highest level of total return consistent with its asset mix. See the Fund Holdings for the portfolio's asset weights. Below, we discuss the factors that affected these asset classes. • Investments in domestic equity holdings contributed meaningfully to performance. U.S. stocks did very well from late 2023 through mid-2024 as a much-anticipated recession failed to arrive. Investors favored stocks benefiting from heavy investment in artificial intelligence-related chips and technologies. Stocks gave back some gains in July, however, amid worries about slowing economic conditions. • The portfolio's non-U.S. equity holdings rose by a smaller amount than U.S. large-cap stocks. The performance disparity can be explained by differences in actual and expected earnings growth—earnings by companies outside the U.S. fell at a faster rate in 2023 and are expected to recover more slowly in 2024 and 2025 than are those of U.S. companies, according to data provider FactSet. • The portfolio's domestic fixed-income holdings contributed to performance. Bond yields were volatile amid changing perceptions of the economy and inflation. The benchmark 10-year Treasury yield started and ended the period at around 4% but went as high as 5% and as low as 3.8%. Reflecting the rally in stocks and strength in corporate earnings, corporate bonds did very well. • Non-U.S. fixed-income holdings produced positive results. Bond prices generally rose and yields fell as manufacturing activity in several developed economies slowed, while inflation concerns eased. That allowed the European Central Bank to cut interest rates. The Bank of Japan, however, raised rates to support its currency and fight imported inflation despite signs of economic weakness. | |
| Line Graph [Table Text Block] | Cumulative Performance (based on an initial $10,000 investment) July 31, 2014, through July 31, 2024 | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns 1 Year 5 Year 10 Year I Class 9.59% 5.85% 5.28% Russell 3000 21.07% 14.23% 12.58% Bloomberg U.S. Aggregate 5.10% 0.19% 1.61% S&P 500 22.15% 15.00% 13.15% Bloomberg U.S. 1-3 Month Treasury Bill 5.51% 2.22% 1.54% | |
| No Deduction of Taxes [Text Block] | The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. | |
| Updated Performance Information Location [Text Block] | Visit americancentury.com for more recent performance information. | |
| Net Assets | $ 323,616,822 | $ 323,616,822 |
| Holdings Count | holding | 831 | 831 |
| Advisory Fees Paid, Amount | $ 1,906,662 | |
| Investment Company, Portfolio Turnover | 30% | |
| Holdings [Text Block] | Fund Holdings Types of Investments in Portfolio (as a % of net assets) Affiliated Funds 37.3% U.S. Treasury Securities 23.8% Common Stocks 18.3% Sovereign Governments and Agencies 5.2% Corporate Bonds 2.9% Collateralized Loan Obligations 1.1% Preferred Stocks 0.4% Asset-Backed Securities 0.4% Municipal Securities 0.3% Collateralized Mortgage Obligations 0.2% Exchange-Traded Funds 0.2% U.S. Government Agency Mortgage-Backed Securities 0.1% Short-Term Investments 9.8% Other Assets and Liabilities 0.0% | |
| C000016334 [Member] | | |
| Shareholder Report [Line Items] | | |
| Fund Name | Strategic Allocation: Conservative Fund | |
| Class Name | A Class | |
| Trading Symbol | ACCAX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Strategic Allocation: Conservative Fund for the period of August 1, 2023 to July 31, 2024. | |
| Shareholder Report Annual or Semi-Annual | 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 year? (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 $101 0.97% | |
| Expenses Paid, Amount | $ 101 | |
| Expense Ratio, Percent | 0.97% | |
| Factors Affecting Performance [Text Block] | What were the key factors that affected the fund’s performance? Strategic Allocation: Conservative Fund A Class returned 9.12% for the reporting period ended July 31, 2024. The fund is an asset allocation fund. That is, it diversifies its assets among various classes of investments such as equity securities, bonds and money market instruments. The fund seeks the highest level of total return consistent with its asset mix. See the Fund Holdings for the portfolio's asset weights. Below, we discuss the factors that affected these asset classes. • Investments in domestic equity holdings contributed meaningfully to performance. U.S. stocks did very well from late 2023 through mid-2024 as a much-anticipated recession failed to arrive. Investors favored stocks benefiting from heavy investment in artificial intelligence-related chips and technologies. Stocks gave back some gains in July, however, amid worries about slowing economic conditions. • The portfolio's non-U.S. equity holdings rose by a smaller amount than U.S. large-cap stocks. The performance disparity can be explained by differences in actual and expected earnings growth—earnings by companies outside the U.S. fell at a faster rate in 2023 and are expected to recover more slowly in 2024 and 2025 than are those of U.S. companies, according to data provider FactSet. • The portfolio's domestic fixed-income holdings contributed to performance. Bond yields were volatile amid changing perceptions of the economy and inflation. The benchmark 10-year Treasury yield started and ended the period at around 4% but went as high as 5% and as low as 3.8%. Reflecting the rally in stocks and strength in corporate earnings, corporate bonds did very well. • Non-U.S. fixed-income holdings produced positive results. Bond prices generally rose and yields fell as manufacturing activity in several developed economies slowed, while inflation concerns eased. That allowed the European Central Bank to cut interest rates. The Bank of Japan, however, raised rates to support its currency and fight imported inflation despite signs of economic weakness. | |
| Line Graph [Table Text Block] | Cumulative Performance (based on an initial $10,000 investment) July 31, 2014, through July 31, 2024 The initial investment is adjusted to reflect the maximum initial sales charge. | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns 1 Year 5 Year 10 Year A Class 9.12% 5.34% 4.82% A Class - with sales charge 2.84% 4.10% 4.20% Russell 3000 21.07% 14.23% 12.58% Bloomberg U.S. Aggregate 5.10% 0.19% 1.61% S&P 500 22.15% 15.00% 13.15% Bloomberg U.S. 1-3 Month Treasury Bill 5.51% 2.22% 1.54% | |
| No Deduction of Taxes [Text Block] | The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. | |
| Updated Performance Information Location [Text Block] | Visit americancentury.com for more recent performance information. | |
| Net Assets | $ 323,616,822 | $ 323,616,822 |
| Holdings Count | holding | 831 | 831 |
| Advisory Fees Paid, Amount | $ 1,906,662 | |
| Investment Company, Portfolio Turnover | 30% | |
| Holdings [Text Block] | Fund Holdings Types of Investments in Portfolio (as a % of net assets) Affiliated Funds 37.3% U.S. Treasury Securities 23.8% Common Stocks 18.3% Sovereign Governments and Agencies 5.2% Corporate Bonds 2.9% Collateralized Loan Obligations 1.1% Preferred Stocks 0.4% Asset-Backed Securities 0.4% Municipal Securities 0.3% Collateralized Mortgage Obligations 0.2% Exchange-Traded Funds 0.2% U.S. Government Agency Mortgage-Backed Securities 0.1% Short-Term Investments 9.8% Other Assets and Liabilities 0.0% | |
| C000016338 [Member] | | |
| Shareholder Report [Line Items] | | |
| Fund Name | Strategic Allocation: Conservative Fund | |
| Class Name | C Class | |
| Trading Symbol | AACCX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Strategic Allocation: Conservative Fund for the period of August 1, 2023 to July 31, 2024. | |
| Shareholder Report Annual or Semi-Annual | 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 year? (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 $179 1.72% | |
| Expenses Paid, Amount | $ 179 | |
| Expense Ratio, Percent | 1.72% | |
| Factors Affecting Performance [Text Block] | What were the key factors that affected the fund’s performance? Strategic Allocation: Conservative Fund C Class returned 8.37% for the reporting period ended July 31, 2024. The fund is an asset allocation fund. That is, it diversifies its assets among various classes of investments such as equity securities, bonds and money market instruments. The fund seeks the highest level of total return consistent with its asset mix. See the Fund Holdings for the portfolio's asset weights. Below, we discuss the factors that affected these asset classes. • Investments in domestic equity holdings contributed meaningfully to performance. U.S. stocks did very well from late 2023 through mid-2024 as a much-anticipated recession failed to arrive. Investors favored stocks benefiting from heavy investment in artificial intelligence-related chips and technologies. Stocks gave back some gains in July, however, amid worries about slowing economic conditions. • The portfolio's non-U.S. equity holdings rose by a smaller amount than U.S. large-cap stocks. The performance disparity can be explained by differences in actual and expected earnings growth—earnings by companies outside the U.S. fell at a faster rate in 2023 and are expected to recover more slowly in 2024 and 2025 than are those of U.S. companies, according to data provider FactSet. • The portfolio's domestic fixed-income holdings contributed to performance. Bond yields were volatile amid changing perceptions of the economy and inflation. The benchmark 10-year Treasury yield started and ended the period at around 4% but went as high as 5% and as low as 3.8%. Reflecting the rally in stocks and strength in corporate earnings, corporate bonds did very well. • Non-U.S. fixed-income holdings produced positive results. Bond prices generally rose and yields fell as manufacturing activity in several developed economies slowed, while inflation concerns eased. That allowed the European Central Bank to cut interest rates. The Bank of Japan, however, raised rates to support its currency and fight imported inflation despite signs of economic weakness. | |
| Line Graph [Table Text Block] | Cumulative Performance (based on an initial $10,000 investment) July 31, 2014, through July 31, 2024 | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns 1 Year 5 Year 10 Year C Class 8.37% 4.58% 4.04% Russell 3000 21.07% 14.23% 12.58% Bloomberg U.S. Aggregate 5.10% 0.19% 1.61% S&P 500 22.15% 15.00% 13.15% Bloomberg U.S. 1-3 Month Treasury Bill 5.51% 2.22% 1.54% | |
| No Deduction of Taxes [Text Block] | The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. | |
| Updated Performance Information Location [Text Block] | Visit americancentury.com for more recent performance information. | |
| Net Assets | $ 323,616,822 | $ 323,616,822 |
| Holdings Count | holding | 831 | 831 |
| Advisory Fees Paid, Amount | $ 1,906,662 | |
| Investment Company, Portfolio Turnover | 30% | |
| Holdings [Text Block] | Fund Holdings Types of Investments in Portfolio (as a % of net assets) Affiliated Funds 37.3% U.S. Treasury Securities 23.8% Common Stocks 18.3% Sovereign Governments and Agencies 5.2% Corporate Bonds 2.9% Collateralized Loan Obligations 1.1% Preferred Stocks 0.4% Asset-Backed Securities 0.4% Municipal Securities 0.3% Collateralized Mortgage Obligations 0.2% Exchange-Traded Funds 0.2% U.S. Government Agency Mortgage-Backed Securities 0.1% Short-Term Investments 9.8% Other Assets and Liabilities 0.0% | |
| C000016332 [Member] | | |
| Shareholder Report [Line Items] | | |
| Fund Name | Strategic Allocation: Conservative Fund | |
| Class Name | R Class | |
| Trading Symbol | AACRX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Strategic Allocation: Conservative Fund for the period of August 1, 2023 to July 31, 2024. | |
| Shareholder Report Annual or Semi-Annual | 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 year? (based on a hypothetical $10,000 investment) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment R Class $127 1.22% | |
| Expenses Paid, Amount | $ 127 | |
| Expense Ratio, Percent | 1.22% | |
| Factors Affecting Performance [Text Block] | What were the key factors that affected the fund’s performance? Strategic Allocation: Conservative Fund R Class returned 8.86% for the reporting period ended July 31, 2024. The fund is an asset allocation fund. That is, it diversifies its assets among various classes of investments such as equity securities, bonds and money market instruments. The fund seeks the highest level of total return consistent with its asset mix. See the Fund Holdings for the portfolio's asset weights. Below, we discuss the factors that affected these asset classes. • Investments in domestic equity holdings contributed meaningfully to performance. U.S. stocks did very well from late 2023 through mid-2024 as a much-anticipated recession failed to arrive. Investors favored stocks benefiting from heavy investment in artificial intelligence-related chips and technologies. Stocks gave back some gains in July, however, amid worries about slowing economic conditions. • The portfolio's non-U.S. equity holdings rose by a smaller amount than U.S. large-cap stocks. The performance disparity can be explained by differences in actual and expected earnings growth—earnings by companies outside the U.S. fell at a faster rate in 2023 and are expected to recover more slowly in 2024 and 2025 than are those of U.S. companies, according to data provider FactSet. • The portfolio's domestic fixed-income holdings contributed to performance. Bond yields were volatile amid changing perceptions of the economy and inflation. The benchmark 10-year Treasury yield started and ended the period at around 4% but went as high as 5% and as low as 3.8%. Reflecting the rally in stocks and strength in corporate earnings, corporate bonds did very well. • Non-U.S. fixed-income holdings produced positive results. Bond prices generally rose and yields fell as manufacturing activity in several developed economies slowed, while inflation concerns eased. That allowed the European Central Bank to cut interest rates. The Bank of Japan, however, raised rates to support its currency and fight imported inflation despite signs of economic weakness. | |
| Line Graph [Table Text Block] | Cumulative Performance (based on an initial $10,000 investment) July 31, 2014, through July 31, 2024 | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns 1 Year 5 Year 10 Year R Class 8.86% 5.13% 4.57% Russell 3000 21.07% 14.23% 12.58% Bloomberg U.S. Aggregate 5.10% 0.19% 1.61% S&P 500 22.15% 15.00% 13.15% Bloomberg U.S. 1-3 Month Treasury Bill 5.51% 2.22% 1.54% | |
| No Deduction of Taxes [Text Block] | The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. | |
| Updated Performance Information Location [Text Block] | Visit americancentury.com for more recent performance information. | |
| Net Assets | $ 323,616,822 | $ 323,616,822 |
| Holdings Count | holding | 831 | 831 |
| Advisory Fees Paid, Amount | $ 1,906,662 | |
| Investment Company, Portfolio Turnover | 30% | |
| Holdings [Text Block] | Fund Holdings Types of Investments in Portfolio (as a % of net assets) Affiliated Funds 37.3% U.S. Treasury Securities 23.8% Common Stocks 18.3% Sovereign Governments and Agencies 5.2% Corporate Bonds 2.9% Collateralized Loan Obligations 1.1% Preferred Stocks 0.4% Asset-Backed Securities 0.4% Municipal Securities 0.3% Collateralized Mortgage Obligations 0.2% Exchange-Traded Funds 0.2% U.S. Government Agency Mortgage-Backed Securities 0.1% Short-Term Investments 9.8% Other Assets and Liabilities 0.0% | |
| C000189656 [Member] | | |
| Shareholder Report [Line Items] | | |
| Fund Name | Strategic Allocation: Conservative Fund | |
| Class Name | R5 Class | |
| Trading Symbol | AACGX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Strategic Allocation: Conservative Fund for the period of August 1, 2023 to July 31, 2024. | |
| Shareholder Report Annual or Semi-Annual | 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 year? (based on a hypothetical $10,000 investment) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment R5 Class $54 0.52% | |
| Expenses Paid, Amount | $ 54 | |
| Expense Ratio, Percent | 0.52% | |
| Factors Affecting Performance [Text Block] | What were the key factors that affected the fund’s performance? Strategic Allocation: Conservative Fund R5 Class returned 9.57% for the reporting period ended July 31, 2024. The fund is an asset allocation fund. That is, it diversifies its assets among various classes of investments such as equity securities, bonds and money market instruments. The fund seeks the highest level of total return consistent with its asset mix. See the Fund Holdings for the portfolio's asset weights. Below, we discuss the factors that affected these asset classes. • Investments in domestic equity holdings contributed meaningfully to performance. U.S. stocks did very well from late 2023 through mid-2024 as a much-anticipated recession failed to arrive. Investors favored stocks benefiting from heavy investment in artificial intelligence-related chips and technologies. Stocks gave back some gains in July, however, amid worries about slowing economic conditions. • The portfolio's non-U.S. equity holdings rose by a smaller amount than U.S. large-cap stocks. The performance disparity can be explained by differences in actual and expected earnings growth—earnings by companies outside the U.S. fell at a faster rate in 2023 and are expected to recover more slowly in 2024 and 2025 than are those of U.S. companies, according to data provider FactSet. • The portfolio's domestic fixed-income holdings contributed to performance. Bond yields were volatile amid changing perceptions of the economy and inflation. The benchmark 10-year Treasury yield started and ended the period at around 4% but went as high as 5% and as low as 3.8%. Reflecting the rally in stocks and strength in corporate earnings, corporate bonds did very well. • Non-U.S. fixed-income holdings produced positive results. Bond prices generally rose and yields fell as manufacturing activity in several developed economies slowed, while inflation concerns eased. That allowed the European Central Bank to cut interest rates. The Bank of Japan, however, raised rates to support its currency and fight imported inflation despite signs of economic weakness. | |
| Line Graph [Table Text Block] | Cumulative Performance (based on an initial $10,000 investment) April 10, 2017, through July 31, 2024 | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns 1 Year 5 Year Since Inception Inception Date R5 Class 9.57% 5.84% 5.87% 4/10/17 Russell 3000 21.07% 14.23% 13.65% — Bloomberg U.S. Aggregate 5.10% 0.19% 1.31% — S&P 500 22.15% 15.00% 14.32% — Bloomberg U.S. 1-3 Month Treasury Bill 5.51% 2.22% 2.06% — | |
| Performance Inception Date | | Apr. 10, 2017 |
| No Deduction of Taxes [Text Block] | The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. | |
| Updated Performance Information Location [Text Block] | Visit americancentury.com for more recent performance information. | |
| Net Assets | $ 323,616,822 | $ 323,616,822 |
| Holdings Count | holding | 831 | 831 |
| Advisory Fees Paid, Amount | $ 1,906,662 | |
| Investment Company, Portfolio Turnover | 30% | |
| Holdings [Text Block] | Fund Holdings Types of Investments in Portfolio (as a % of net assets) Affiliated Funds 37.3% U.S. Treasury Securities 23.8% Common Stocks 18.3% Sovereign Governments and Agencies 5.2% Corporate Bonds 2.9% Collateralized Loan Obligations 1.1% Preferred Stocks 0.4% Asset-Backed Securities 0.4% Municipal Securities 0.3% Collateralized Mortgage Obligations 0.2% Exchange-Traded Funds 0.2% U.S. Government Agency Mortgage-Backed Securities 0.1% Short-Term Investments 9.8% Other Assets and Liabilities 0.0% | |
| C000131621 [Member] | | |
| Shareholder Report [Line Items] | | |
| Fund Name | Strategic Allocation: Conservative Fund | |
| Class Name | R6 Class | |
| Trading Symbol | AACDX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Strategic Allocation: Conservative Fund for the period of August 1, 2023 to July 31, 2024. | |
| Shareholder Report Annual or Semi-Annual | 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 year? (based on a hypothetical $10,000 investment) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment R6 Class $39 0.37% | |
| Expenses Paid, Amount | $ 39 | |
| Expense Ratio, Percent | 0.37% | |
| Factors Affecting Performance [Text Block] | What were the key factors that affected the fund’s performance? Strategic Allocation: Conservative Fund R6 Class returned 9.76% for the reporting period ended July 31, 2024. The fund is an asset allocation fund. That is, it diversifies its assets among various classes of investments such as equity securities, bonds and money market instruments. The fund seeks the highest level of total return consistent with its asset mix. See the Fund Holdings for the portfolio's asset weights. Below, we discuss the factors that affected these asset classes. • Investments in domestic equity holdings contributed meaningfully to performance. U.S. stocks did very well from late 2023 through mid-2024 as a much-anticipated recession failed to arrive. Investors favored stocks benefiting from heavy investment in artificial intelligence-related chips and technologies. Stocks gave back some gains in July, however, amid worries about slowing economic conditions. • The portfolio's non-U.S. equity holdings rose by a smaller amount than U.S. large-cap stocks. The performance disparity can be explained by differences in actual and expected earnings growth—earnings by companies outside the U.S. fell at a faster rate in 2023 and are expected to recover more slowly in 2024 and 2025 than are those of U.S. companies, according to data provider FactSet. • The portfolio's domestic fixed-income holdings contributed to performance. Bond yields were volatile amid changing perceptions of the economy and inflation. The benchmark 10-year Treasury yield started and ended the period at around 4% but went as high as 5% and as low as 3.8%. Reflecting the rally in stocks and strength in corporate earnings, corporate bonds did very well. • Non-U.S. fixed-income holdings produced positive results. Bond prices generally rose and yields fell as manufacturing activity in several developed economies slowed, while inflation concerns eased. That allowed the European Central Bank to cut interest rates. The Bank of Japan, however, raised rates to support its currency and fight imported inflation despite signs of economic weakness. | |
| Line Graph [Table Text Block] | Cumulative Performance (based on an initial $10,000 investment) July 31, 2014, through July 31, 2024 | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns 1 Year 5 Year 10 Year R6 Class 9.76% 5.97% 5.44% Russell 3000 21.07% 14.23% 12.58% Bloomberg U.S. Aggregate 5.10% 0.19% 1.61% S&P 500 22.15% 15.00% 13.15% Bloomberg U.S. 1-3 Month Treasury Bill 5.51% 2.22% 1.54% | |
| No Deduction of Taxes [Text Block] | The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. | |
| Updated Performance Information Location [Text Block] | Visit americancentury.com for more recent performance information. | |
| Net Assets | $ 323,616,822 | $ 323,616,822 |
| Holdings Count | holding | 831 | 831 |
| Advisory Fees Paid, Amount | $ 1,906,662 | |
| Investment Company, Portfolio Turnover | 30% | |
| Holdings [Text Block] | Fund Holdings Types of Investments in Portfolio (as a % of net assets) Affiliated Funds 37.3% U.S. Treasury Securities 23.8% Common Stocks 18.3% Sovereign Governments and Agencies 5.2% Corporate Bonds 2.9% Collateralized Loan Obligations 1.1% Preferred Stocks 0.4% Asset-Backed Securities 0.4% Municipal Securities 0.3% Collateralized Mortgage Obligations 0.2% Exchange-Traded Funds 0.2% U.S. Government Agency Mortgage-Backed Securities 0.1% Short-Term Investments 9.8% Other Assets and Liabilities 0.0% | |
| C000016325 [Member] | | |
| Shareholder Report [Line Items] | | |
| Fund Name | Strategic Allocation: Moderate Fund | |
| Class Name | Investor Class | |
| Trading Symbol | TWSMX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Strategic Allocation: Moderate Fund for the period of August 1, 2023 to July 31, 2024. | |
| Shareholder Report Annual or Semi-Annual | 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 year? (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 $73 0.69% | |
| Expenses Paid, Amount | $ 73 | |
| Expense Ratio, Percent | 0.69% | |
| Factors Affecting Performance [Text Block] | What were the key factors that affected the fund’s performance? Strategic Allocation: Moderate Fund Investor Class returned 11.30% for the reporting period ended July 31, 2024. The fund is an asset allocation fund. That is, it diversifies its assets among various classes of investments such as equity securities, bonds and money market instruments. The fund seeks the highest level of total return consistent with its asset mix. See the Fund Holdings for the portfolio's asset weights. Below, we discuss the factors that affected these asset classes. • Investments in domestic equity holdings contributed meaningfully to performance. U.S. stocks did very well from late 2023 through mid-2024 as a much-anticipated recession failed to arrive. Investors favored stocks benefiting from heavy investment in artificial intelligence-related chips and technologies. Stocks gave back some gains in July, however, amid worries about slowing economic conditions. • The portfolio's non-U.S. equity holdings also rose but by a smaller amount than U.S. large-cap stocks. Signs of slowing economic growth led the European Central Bank to lower short-term interest rates for the first time in almost five years in June 2024. Emerging markets equities generally fared better as Taiwanese and South Korean companies benefited from strength in technology stocks. • The portfolio's domestic fixed-income holdings contributed to performance. Bond yields were volatile amid changing perceptions of the economy and inflation. The benchmark 10-year Treasury yield started and ended the period at around 4% but went as high as 5% and as low as 3.8%. Reflecting the rally in stocks and strength in corporate earnings, corporate bonds did very well. • Non-U.S. fixed-income holdings produced positive results. Bond prices generally rose and yields fell as manufacturing activity in several developed economies slowed, while inflation concerns eased. That allowed the European Central Bank to cut interest rates. The Bank of Japan, however, raised rates to support its currency and fight imported inflation despite signs of economic weakness. | |
| Line Graph [Table Text Block] | Cumulative Performance (based on an initial $10,000 investment) July 31, 2014, through July 31, 2024 | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns 1 Year 5 Year 10 Year Investor Class 11.30% 7.48% 6.63% Russell 3000 21.07% 14.23% 12.58% Bloomberg U.S. Aggregate 5.10% 0.19% 1.61% S&P 500 22.15% 15.00% 13.15% Bloomberg U.S. 1-3 Month Treasury Bill 5.51% 2.22% 1.54% | |
| No Deduction of Taxes [Text Block] | The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. | |
| Updated Performance Information Location [Text Block] | Visit americancentury.com for more recent performance information. | |
| Net Assets | $ 754,098,529 | $ 754,098,529 |
| Holdings Count | holding | 838 | 838 |
| Advisory Fees Paid, Amount | $ 4,378,042 | |
| Investment Company, Portfolio Turnover | 28% | |
| Holdings [Text Block] | Fund Holdings Types of Investments in Portfolio (as a % of net assets) Affiliated Funds 46.0% Common Stocks 25.7% U.S. Treasury Securities 14.0% Sovereign Governments and Agencies 2.9% Corporate Bonds 1.7% Collateralized Loan Obligations 1.0% Asset-Backed Securities 0.2% Collateralized Mortgage Obligations 0.2% Preferred Stocks 0.2% U.S. Government Agency Mortgage-Backed Securities 0.1% Municipal Securities 0.1% Exchange-Traded Funds 0.0% Short-Term Investments 8.9% Other Assets and Liabilities (1.0)% | |
| C000016327 [Member] | | |
| Shareholder Report [Line Items] | | |
| Fund Name | Strategic Allocation: Moderate Fund | |
| Class Name | I Class | |
| Trading Symbol | ASAMX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Strategic Allocation: Moderate Fund for the period of August 1, 2023 to July 31, 2024. | |
| Shareholder Report Annual or Semi-Annual | 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 year? (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 $52 0.49% | |
| Expenses Paid, Amount | $ 52 | |
| Expense Ratio, Percent | 0.49% | |
| Factors Affecting Performance [Text Block] | What were the key factors that affected the fund’s performance? Strategic Allocation: Moderate Fund I Class returned 11.50% for the reporting period ended July 31, 2024. The fund is an asset allocation fund. That is, it diversifies its assets among various classes of investments such as equity securities, bonds and money market instruments. The fund seeks the highest level of total return consistent with its asset mix. See the Fund Holdings for the portfolio's asset weights. Below, we discuss the factors that affected these asset classes. • Investments in domestic equity holdings contributed meaningfully to performance. U.S. stocks did very well from late 2023 through mid-2024 as a much-anticipated recession failed to arrive. Investors favored stocks benefiting from heavy investment in artificial intelligence-related chips and technologies. Stocks gave back some gains in July, however, amid worries about slowing economic conditions. • The portfolio's non-U.S. equity holdings also rose but by a smaller amount than U.S. large-cap stocks. Signs of slowing economic growth led the European Central Bank to lower short-term interest rates for the first time in almost five years in June 2024. Emerging markets equities generally fared better as Taiwanese and South Korean companies benefited from strength in technology stocks. • The portfolio's domestic fixed-income holdings contributed to performance. Bond yields were volatile amid changing perceptions of the economy and inflation. The benchmark 10-year Treasury yield started and ended the period at around 4% but went as high as 5% and as low as 3.8%. Reflecting the rally in stocks and strength in corporate earnings, corporate bonds did very well. • Non-U.S. fixed-income holdings produced positive results. Bond prices generally rose and yields fell as manufacturing activity in several developed economies slowed, while inflation concerns eased. That allowed the European Central Bank to cut interest rates. The Bank of Japan, however, raised rates to support its currency and fight imported inflation despite signs of economic weakness. | |
| Line Graph [Table Text Block] | Cumulative Performance (based on an initial $10,000 investment) July 31, 2014, through July 31, 2024 | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns 1 Year 5 Year 10 Year I Class 11.50% 7.73% 6.85% Russell 3000 21.07% 14.23% 12.58% Bloomberg U.S. Aggregate 5.10% 0.19% 1.61% S&P 500 22.15% 15.00% 13.15% Bloomberg U.S. 1-3 Month Treasury Bill 5.51% 2.22% 1.54% | |
| No Deduction of Taxes [Text Block] | The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. | |
| Updated Performance Information Location [Text Block] | Visit americancentury.com for more recent performance information. | |
| Net Assets | $ 754,098,529 | $ 754,098,529 |
| Holdings Count | holding | 838 | 838 |
| Advisory Fees Paid, Amount | $ 4,378,042 | |
| Investment Company, Portfolio Turnover | 28% | |
| Holdings [Text Block] | Fund Holdings Types of Investments in Portfolio (as a % of net assets) Affiliated Funds 46.0% Common Stocks 25.7% U.S. Treasury Securities 14.0% Sovereign Governments and Agencies 2.9% Corporate Bonds 1.7% Collateralized Loan Obligations 1.0% Asset-Backed Securities 0.2% Collateralized Mortgage Obligations 0.2% Preferred Stocks 0.2% U.S. Government Agency Mortgage-Backed Securities 0.1% Municipal Securities 0.1% Exchange-Traded Funds 0.0% Short-Term Investments 8.9% Other Assets and Liabilities (1.0)% | |
| C000016326 [Member] | | |
| Shareholder Report [Line Items] | | |
| Fund Name | Strategic Allocation: Moderate Fund | |
| Class Name | A Class | |
| Trading Symbol | ACOAX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Strategic Allocation: Moderate Fund for the period of August 1, 2023 to July 31, 2024. | |
| Shareholder Report Annual or Semi-Annual | 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 year? (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 $99 0.94% | |
| Expenses Paid, Amount | $ 99 | |
| Expense Ratio, Percent | 0.94% | |
| Factors Affecting Performance [Text Block] | What were the key factors that affected the fund’s performance? Strategic Allocation: Moderate Fund A Class returned 10.89% for the reporting period ended July 31, 2024. The fund is an asset allocation fund. That is, it diversifies its assets among various classes of investments such as equity securities, bonds and money market instruments. The fund seeks the highest level of total return consistent with its asset mix. See the Fund Holdings for the portfolio's asset weights. Below, we discuss the factors that affected these asset classes. • Investments in domestic equity holdings contributed meaningfully to performance. U.S. stocks did very well from late 2023 through mid-2024 as a much-anticipated recession failed to arrive. Investors favored stocks benefiting from heavy investment in artificial intelligence-related chips and technologies. Stocks gave back some gains in July, however, amid worries about slowing economic conditions. • The portfolio's non-U.S. equity holdings also rose but by a smaller amount than U.S. large-cap stocks. Signs of slowing economic growth led the European Central Bank to lower short-term interest rates for the first time in almost five years in June 2024. Emerging markets equities generally fared better as Taiwanese and South Korean companies benefited from strength in technology stocks. • The portfolio's domestic fixed-income holdings contributed to performance. Bond yields were volatile amid changing perceptions of the economy and inflation. The benchmark 10-year Treasury yield started and ended the period at around 4% but went as high as 5% and as low as 3.8%. Reflecting the rally in stocks and strength in corporate earnings, corporate bonds did very well. • Non-U.S. fixed-income holdings produced positive results. Bond prices generally rose and yields fell as manufacturing activity in several developed economies slowed, while inflation concerns eased. That allowed the European Central Bank to cut interest rates. The Bank of Japan, however, raised rates to support its currency and fight imported inflation despite signs of economic weakness. | |
| Line Graph [Table Text Block] | Cumulative Performance (based on an initial $10,000 investment) July 31, 2014, through July 31, 2024 The initial investment is adjusted to reflect the maximum initial sales charge. | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns 1 Year 5 Year 10 Year A Class 10.89% 7.21% 6.35% A Class - with sales charge 4.51% 5.95% 5.73% Russell 3000 21.07% 14.23% 12.58% Bloomberg U.S. Aggregate 5.10% 0.19% 1.61% S&P 500 22.15% 15.00% 13.15% Bloomberg U.S. 1-3 Month Treasury Bill 5.51% 2.22% 1.54% | |
| No Deduction of Taxes [Text Block] | The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. | |
| Updated Performance Information Location [Text Block] | Visit americancentury.com for more recent performance information. | |
| Net Assets | $ 754,098,529 | $ 754,098,529 |
| Holdings Count | holding | 838 | 838 |
| Advisory Fees Paid, Amount | $ 4,378,042 | |
| Investment Company, Portfolio Turnover | 28% | |
| Holdings [Text Block] | Fund Holdings Types of Investments in Portfolio (as a % of net assets) Affiliated Funds 46.0% Common Stocks 25.7% U.S. Treasury Securities 14.0% Sovereign Governments and Agencies 2.9% Corporate Bonds 1.7% Collateralized Loan Obligations 1.0% Asset-Backed Securities 0.2% Collateralized Mortgage Obligations 0.2% Preferred Stocks 0.2% U.S. Government Agency Mortgage-Backed Securities 0.1% Municipal Securities 0.1% Exchange-Traded Funds 0.0% Short-Term Investments 8.9% Other Assets and Liabilities (1.0)% | |
| C000016330 [Member] | | |
| Shareholder Report [Line Items] | | |
| Fund Name | Strategic Allocation: Moderate Fund | |
| Class Name | C Class | |
| Trading Symbol | ASTCX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Strategic Allocation: Moderate Fund for the period of August 1, 2023 to July 31, 2024. | |
| Shareholder Report Annual or Semi-Annual | 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 year? (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 $178 1.69% | |
| Expenses Paid, Amount | $ 178 | |
| Expense Ratio, Percent | 1.69% | |
| Factors Affecting Performance [Text Block] | What were the key factors that affected the fund’s performance? Strategic Allocation: Moderate Fund C Class returned 10.09% for the reporting period ended July 31, 2024. The fund is an asset allocation fund. That is, it diversifies its assets among various classes of investments such as equity securities, bonds and money market instruments. The fund seeks the highest level of total return consistent with its asset mix. See the Fund Holdings for the portfolio's asset weights. Below, we discuss the factors that affected these asset classes. • Investments in domestic equity holdings contributed meaningfully to performance. U.S. stocks did very well from late 2023 through mid-2024 as a much-anticipated recession failed to arrive. Investors favored stocks benefiting from heavy investment in artificial intelligence-related chips and technologies. Stocks gave back some gains in July, however, amid worries about slowing economic conditions. • The portfolio's non-U.S. equity holdings also rose but by a smaller amount than U.S. large-cap stocks. Signs of slowing economic growth led the European Central Bank to lower short-term interest rates for the first time in almost five years in June 2024. Emerging markets equities generally fared better as Taiwanese and South Korean companies benefited from strength in technology stocks. • The portfolio's domestic fixed-income holdings contributed to performance. Bond yields were volatile amid changing perceptions of the economy and inflation. The benchmark 10-year Treasury yield started and ended the period at around 4% but went as high as 5% and as low as 3.8%. Reflecting the rally in stocks and strength in corporate earnings, corporate bonds did very well. • Non-U.S. fixed-income holdings produced positive results. Bond prices generally rose and yields fell as manufacturing activity in several developed economies slowed, while inflation concerns eased. That allowed the European Central Bank to cut interest rates. The Bank of Japan, however, raised rates to support its currency and fight imported inflation despite signs of economic weakness. | |
| Line Graph [Table Text Block] | Cumulative Performance (based on an initial $10,000 investment) July 31, 2014, through July 31, 2024 | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns 1 Year 5 Year 10 Year C Class 10.09% 6.43% 5.57% Russell 3000 21.07% 14.23% 12.58% Bloomberg U.S. Aggregate 5.10% 0.19% 1.61% S&P 500 22.15% 15.00% 13.15% Bloomberg U.S. 1-3 Month Treasury Bill 5.51% 2.22% 1.54% | |
| No Deduction of Taxes [Text Block] | The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. | |
| Updated Performance Information Location [Text Block] | Visit americancentury.com for more recent performance information. | |
| Net Assets | $ 754,098,529 | $ 754,098,529 |
| Holdings Count | holding | 838 | 838 |
| Advisory Fees Paid, Amount | $ 4,378,042 | |
| Investment Company, Portfolio Turnover | 28% | |
| Holdings [Text Block] | Fund Holdings Types of Investments in Portfolio (as a % of net assets) Affiliated Funds 46.0% Common Stocks 25.7% U.S. Treasury Securities 14.0% Sovereign Governments and Agencies 2.9% Corporate Bonds 1.7% Collateralized Loan Obligations 1.0% Asset-Backed Securities 0.2% Collateralized Mortgage Obligations 0.2% Preferred Stocks 0.2% U.S. Government Agency Mortgage-Backed Securities 0.1% Municipal Securities 0.1% Exchange-Traded Funds 0.0% Short-Term Investments 8.9% Other Assets and Liabilities (1.0)% | |
| C000016331 [Member] | | |
| Shareholder Report [Line Items] | | |
| Fund Name | Strategic Allocation: Moderate Fund | |
| Class Name | R Class | |
| Trading Symbol | ASMRX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Strategic Allocation: Moderate Fund for the period of August 1, 2023 to July 31, 2024. | |
| Shareholder Report Annual or Semi-Annual | 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 year? (based on a hypothetical $10,000 investment) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment R Class $125 1.19% | |
| Expenses Paid, Amount | $ 125 | |
| Expense Ratio, Percent | 1.19% | |
| Factors Affecting Performance [Text Block] | What were the key factors that affected the fund’s performance? Strategic Allocation: Moderate Fund R Class returned 10.55% for the reporting period ended July 31, 2024. The fund is an asset allocation fund. That is, it diversifies its assets among various classes of investments such as equity securities, bonds and money market instruments. The fund seeks the highest level of total return consistent with its asset mix. See the Fund Holdings for the portfolio's asset weights. Below, we discuss the factors that affected these asset classes. • Investments in domestic equity holdings contributed meaningfully to performance. U.S. stocks did very well from late 2023 through mid-2024 as a much-anticipated recession failed to arrive. Investors favored stocks benefiting from heavy investment in artificial intelligence-related chips and technologies. Stocks gave back some gains in July, however, amid worries about slowing economic conditions. • The portfolio's non-U.S. equity holdings also rose but by a smaller amount than U.S. large-cap stocks. Signs of slowing economic growth led the European Central Bank to lower short-term interest rates for the first time in almost five years in June 2024. Emerging markets equities generally fared better as Taiwanese and South Korean companies benefited from strength in technology stocks. • The portfolio's domestic fixed-income holdings contributed to performance. Bond yields were volatile amid changing perceptions of the economy and inflation. The benchmark 10-year Treasury yield started and ended the period at around 4% but went as high as 5% and as low as 3.8%. Reflecting the rally in stocks and strength in corporate earnings, corporate bonds did very well. • Non-U.S. fixed-income holdings produced positive results. Bond prices generally rose and yields fell as manufacturing activity in several developed economies slowed, while inflation concerns eased. That allowed the European Central Bank to cut interest rates. The Bank of Japan, however, raised rates to support its currency and fight imported inflation despite signs of economic weakness. | |
| Line Graph [Table Text Block] | Cumulative Performance (based on an initial $10,000 investment) July 31, 2014, through July 31, 2024 | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns 1 Year 5 Year 10 Year R Class 10.55% 6.94% 6.09% Russell 3000 21.07% 14.23% 12.58% Bloomberg U.S. Aggregate 5.10% 0.19% 1.61% S&P 500 22.15% 15.00% 13.15% Bloomberg U.S. 1-3 Month Treasury Bill 5.51% 2.22% 1.54% | |
| No Deduction of Taxes [Text Block] | The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. | |
| Updated Performance Information Location [Text Block] | Visit americancentury.com for more recent performance information. | |
| Net Assets | $ 754,098,529 | $ 754,098,529 |
| Holdings Count | holding | 838 | 838 |
| Advisory Fees Paid, Amount | $ 4,378,042 | |
| Investment Company, Portfolio Turnover | 28% | |
| Holdings [Text Block] | Fund Holdings Types of Investments in Portfolio (as a % of net assets) Affiliated Funds 46.0% Common Stocks 25.7% U.S. Treasury Securities 14.0% Sovereign Governments and Agencies 2.9% Corporate Bonds 1.7% Collateralized Loan Obligations 1.0% Asset-Backed Securities 0.2% Collateralized Mortgage Obligations 0.2% Preferred Stocks 0.2% U.S. Government Agency Mortgage-Backed Securities 0.1% Municipal Securities 0.1% Exchange-Traded Funds 0.0% Short-Term Investments 8.9% Other Assets and Liabilities (1.0)% | |
| C000189655 [Member] | | |
| Shareholder Report [Line Items] | | |
| Fund Name | Strategic Allocation: Moderate Fund | |
| Class Name | R5 Class | |
| Trading Symbol | ASMUX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Strategic Allocation: Moderate Fund for the period of August 1, 2023 to July 31, 2024. | |
| Shareholder Report Annual or Semi-Annual | 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 year? (based on a hypothetical $10,000 investment) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment R5 Class $52 0.49% | |
| Expenses Paid, Amount | $ 52 | |
| Expense Ratio, Percent | 0.49% | |
| Factors Affecting Performance [Text Block] | What were the key factors that affected the fund’s performance? Strategic Allocation: Moderate Fund R5 Class returned 11.50% for the reporting period ended July 31, 2024. The fund is an asset allocation fund. That is, it diversifies its assets among various classes of investments such as equity securities, bonds and money market instruments. The fund seeks the highest level of total return consistent with its asset mix. See the Fund Holdings for the portfolio's asset weights. Below, we discuss the factors that affected these asset classes. • Investments in domestic equity holdings contributed meaningfully to performance. U.S. stocks did very well from late 2023 through mid-2024 as a much-anticipated recession failed to arrive. Investors favored stocks benefiting from heavy investment in artificial intelligence-related chips and technologies. Stocks gave back some gains in July, however, amid worries about slowing economic conditions. • The portfolio's non-U.S. equity holdings also rose but by a smaller amount than U.S. large-cap stocks. Signs of slowing economic growth led the European Central Bank to lower short-term interest rates for the first time in almost five years in June 2024. Emerging markets equities generally fared better as Taiwanese and South Korean companies benefited from strength in technology stocks. • The portfolio's domestic fixed-income holdings contributed to performance. Bond yields were volatile amid changing perceptions of the economy and inflation. The benchmark 10-year Treasury yield started and ended the period at around 4% but went as high as 5% and as low as 3.8%. Reflecting the rally in stocks and strength in corporate earnings, corporate bonds did very well. • Non-U.S. fixed-income holdings produced positive results. Bond prices generally rose and yields fell as manufacturing activity in several developed economies slowed, while inflation concerns eased. That allowed the European Central Bank to cut interest rates. The Bank of Japan, however, raised rates to support its currency and fight imported inflation despite signs of economic weakness. | |
| Line Graph [Table Text Block] | Cumulative Performance (based on an initial $10,000 investment) April 10, 2017, through July 31, 2024 | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns 1 Year 5 Year Since Inception Inception Date R5 Class 11.50% 7.69% 7.64% 4/10/17 Russell 3000 21.07% 14.23% 13.65% — Bloomberg U.S. Aggregate 5.10% 0.19% 1.31% — S&P 500 22.15% 15.00% 14.32% — Bloomberg U.S. 1-3 Month Treasury Bill 5.51% 2.22% 2.06% — | |
| Performance Inception Date | | Apr. 10, 2017 |
| No Deduction of Taxes [Text Block] | The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. | |
| Updated Performance Information Location [Text Block] | Visit americancentury.com for more recent performance information. | |
| Net Assets | $ 754,098,529 | $ 754,098,529 |
| Holdings Count | holding | 838 | 838 |
| Advisory Fees Paid, Amount | $ 4,378,042 | |
| Investment Company, Portfolio Turnover | 28% | |
| Holdings [Text Block] | Fund Holdings Types of Investments in Portfolio (as a % of net assets) Affiliated Funds 46.0% Common Stocks 25.7% U.S. Treasury Securities 14.0% Sovereign Governments and Agencies 2.9% Corporate Bonds 1.7% Collateralized Loan Obligations 1.0% Asset-Backed Securities 0.2% Collateralized Mortgage Obligations 0.2% Preferred Stocks 0.2% U.S. Government Agency Mortgage-Backed Securities 0.1% Municipal Securities 0.1% Exchange-Traded Funds 0.0% Short-Term Investments 8.9% Other Assets and Liabilities (1.0)% | |
| C000131620 [Member] | | |
| Shareholder Report [Line Items] | | |
| Fund Name | Strategic Allocation: Moderate Fund | |
| Class Name | R6 Class | |
| Trading Symbol | ASMDX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Strategic Allocation: Moderate Fund for the period of August 1, 2023 to July 31, 2024. | |
| Shareholder Report Annual or Semi-Annual | 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 year? (based on a hypothetical $10,000 investment) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment R6 Class $36 0.34% | |
| Expenses Paid, Amount | $ 36 | |
| Expense Ratio, Percent | 0.34% | |
| Factors Affecting Performance [Text Block] | What were the key factors that affected the fund’s performance? Strategic Allocation: Moderate Fund R6 Class returned 11.52% for the reporting period ended July 31, 2024. The fund is an asset allocation fund. That is, it diversifies its assets among various classes of investments such as equity securities, bonds and money market instruments. The fund seeks the highest level of total return consistent with its asset mix. See the Fund Holdings for the portfolio's asset weights. Below, we discuss the factors that affected these asset classes. • Investments in domestic equity holdings contributed meaningfully to performance. U.S. stocks did very well from late 2023 through mid-2024 as a much-anticipated recession failed to arrive. Investors favored stocks benefiting from heavy investment in artificial intelligence-related chips and technologies. Stocks gave back some gains in July, however, amid worries about slowing economic conditions. • The portfolio's non-U.S. equity holdings also rose but by a smaller amount than U.S. large-cap stocks. Signs of slowing economic growth led the European Central Bank to lower short-term interest rates for the first time in almost five years in June 2024. Emerging markets equities generally fared better as Taiwanese and South Korean companies benefited from strength in technology stocks. • The portfolio's domestic fixed-income holdings contributed to performance. Bond yields were volatile amid changing perceptions of the economy and inflation. The benchmark 10-year Treasury yield started and ended the period at around 4% but went as high as 5% and as low as 3.8%. Reflecting the rally in stocks and strength in corporate earnings, corporate bonds did very well. • Non-U.S. fixed-income holdings produced positive results. Bond prices generally rose and yields fell as manufacturing activity in several developed economies slowed, while inflation concerns eased. That allowed the European Central Bank to cut interest rates. The Bank of Japan, however, raised rates to support its currency and fight imported inflation despite signs of economic weakness. | |
| Line Graph [Table Text Block] | Cumulative Performance (based on an initial $10,000 investment) July 31, 2014, through July 31, 2024 | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns 1 Year 5 Year 10 Year R6 Class 11.52% 7.87% 6.99% Russell 3000 21.07% 14.23% 12.58% Bloomberg U.S. Aggregate 5.10% 0.19% 1.61% S&P 500 22.15% 15.00% 13.15% Bloomberg U.S. 1-3 Month Treasury Bill 5.51% 2.22% 1.54% | |
| No Deduction of Taxes [Text Block] | The opinions expressed are those of American Century Investments and are no guarantee of the future performance of any American Century Investments fund. This information is for educational purposes only and is not intended as investment advice. Data reflects past performance, assumes reinvestment of dividends and capital gains and is no guarantee of future results. Current performance may be higher or lower than data shown. Investment return and principal value will fluctuate and redemption value may be more or less than original cost, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. | |
| Updated Performance Information Location [Text Block] | Visit americancentury.com for more recent performance information. | |
| Net Assets | $ 754,098,529 | $ 754,098,529 |
| Holdings Count | holding | 838 | 838 |
| Advisory Fees Paid, Amount | $ 4,378,042 | |
| Investment Company, Portfolio Turnover | 28% | |
| Holdings [Text Block] | Fund Holdings Types of Investments in Portfolio (as a % of net assets) Affiliated Funds 46.0% Common Stocks 25.7% U.S. Treasury Securities 14.0% Sovereign Governments and Agencies 2.9% Corporate Bonds 1.7% Collateralized Loan Obligations 1.0% Asset-Backed Securities 0.2% Collateralized Mortgage Obligations 0.2% Preferred Stocks 0.2% U.S. Government Agency Mortgage-Backed Securities 0.1% Municipal Securities 0.1% Exchange-Traded Funds 0.0% Short-Term Investments 8.9% Other Assets and Liabilities (1.0)% | |
