Net Assets Investment Company, Portfolio Turnover C000198563 [Member] American Funds® College 2036 Fund - Class 529-A Investment Type [Axis] Growth-and-income funds [Member] Equity-income funds [Member] Other assets less liabilities [Member] Growth funds [Member] Balanced funds [Member] Fixed income funds [Member] C000198564 [Member] American Funds® College 2036 Fund - Class 529-C C000198565 [Member] American Funds® College 2036 Fund - Class 529-E C000198567 [Member] American Funds® College 2036 Fund - Class 529-T C000198566 [Member] American Funds® College 2036 Fund - Class 529-F-1 C000224617 [Member] American Funds® College 2036 Fund - Class 529-F-2 C000224618 [Member] American Funds® College 2036 Fund - Class 529-F-3 C000150471 [Member] American Funds College 2033 Fund® - Class 529-A C000150473 [Member] American Funds College 2033 Fund® - Class 529-C C000150474 [Member] American Funds College 2033 Fund® - Class 529-E C000189506 [Member] American Funds College 2033 Fund® - Class 529-T C000150475 [Member] American Funds College 2033 Fund® - Class 529-F-1 C000224615 [Member] American Funds College 2033 Fund® - Class 529-F-2 C000224616 [Member] American Funds College 2033 Fund® - Class 529-F-3 C000115875 [Member] American Funds College 2030 Fund® - Class 529-A American Funds College 2030 Fund® - Class 529-C American Funds College 2030 Fund® - Class 529-E American Funds College 2030 Fund® - Class 529-T American Funds College 2030 Fund® - Class 529-F-1 American Funds College 2030 Fund® - Class 529-F-2 American Funds College 2030 Fund® - Class 529-F-3 American Funds College 2027 Fund® - Class 529-A American Funds College 2027 Fund® - Class 529-C American Funds College 2027 Fund® - Class 529-E American Funds College 2027 Fund® - Class 529-T American Funds College 2027 Fund® - Class 529-F-1 American Funds College 2027 Fund® - Class 529-F-2 American Funds College 2027 Fund® - Class 529-F-3 American Funds College Enrollment Fund® - Class 529-A American Funds College Enrollment Fund® - Class 529-C American Funds College Enrollment Fund® - Class 529-E American Funds College Enrollment Fund® - Class 529-T American Funds College Enrollment Fund® - Class 529-F-1 American Funds College Enrollment Fund® - Class 529-F-2 American Funds College Enrollment Fund® - Class 529-F-3 C000247303 [Member] American Funds® College 2042 Fund - Class 529-A C000247305 [Member] American Funds® College 2042 Fund - Class 529-C C000247304 [Member] American Funds® College 2042 Fund - Class 529-E C000247301 [Member] American Funds® College 2042 Fund - Class 529-T C000247306 [Member] American Funds® College 2042 Fund - Class 529-F-1 C000247300 [Member] American Funds® College 2042 Fund - Class 529-F-2 C000247302 [Member] American Funds® College 2042 Fund - Class 529-F-3 C000223952 [Member] American Funds® College 2039 Fund - Class 529-A C000223954 [Member] American Funds® College 2039 Fund - Class 529-C C000223950 [Member] American Funds® College 2039 Fund - Class 529-E C000223953 [Member] American Funds® College 2039 Fund - Class 529-T C000223949 [Member] American Funds® College 2039 Fund - Class 529-F-1 C000223948 [Member] American Funds® College 2039 Fund - Class 529-F-2 C000223951 [Member] American Funds® College 2039 Fund - Class 529-F-3