Net Assets Investment Company, Portfolio Turnover C000210551 [Member] American Funds Multi-Sector Income Fund - Class A C000210556 [Member] American Funds Multi-Sector Income Fund - Class R-6 C000210540 [Member] American Funds Multi-Sector Income Fund - Class R-5E C000210541 [Member] American Funds Multi-Sector Income Fund - Class R-5 C000210545 [Member] American Funds Multi-Sector Income Fund - Class R-2 C000210544 [Member] American Funds Multi-Sector Income Fund - Class R-2E C000210543 [Member] American Funds Multi-Sector Income Fund - Class R-3 C000210542 [Member] American Funds Multi-Sector Income Fund - Class R-4 C000210550 [Member] American Funds Multi-Sector Income Fund - Class C C000210549 [Member] American Funds Multi-Sector Income Fund - Class F-1 C000210548 [Member] American Funds Multi-Sector Income Fund - Class F-2 C000210547 [Member] American Funds Multi-Sector Income Fund - Class F-3 C000210539 [Member] American Funds Multi-Sector Income Fund - Class 529-A C000210555 [Member] American Funds Multi-Sector Income Fund - Class 529-C C000210554 [Member] American Funds Multi-Sector Income Fund - Class 529-E C000220532 [Member] American Funds Multi-Sector Income Fund - Class 529-F-2 C000220533 [Member] American Funds Multi-Sector Income Fund - Class 529-F-3 C000210546 [Member] American Funds Multi-Sector Income Fund - Class R-1 Investment Type [Axis] U.S. Corporate Bonds And Notes [Member] U.S. corporate bonds & notes [Member] Corporate Bonds And Notes Of Issuers Outside The U.S. [Member] Corporate bonds & notes of issuers outside the U.S. [Member] Mortgage-backed obligations [Member] Bonds And Notes Of Governments And Government Agencies Outside The U.S. [Member] Bonds & notes of governments & government agencies outside the U.S. [Member] Asset-backed obligations [Member] Loans [Member] U.S. Treasury Bonds And Notes [Member] U.S. Treasury bonds & notes [Member] Municipals [Member] Federal Agency Bonds And Notes [Member] Federal agency bonds & notes [Member] Common Stock [Member] Other securities [Member] Options purchased [Member] Short Term Securities And Other Assets Less Liabilities [Member] Short-term securities & other assets less liabilities [Member]