| Label                                                    | **Element**              | Value                                                                                                                                                                                                                |
|----------------------------------------------------------|--------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| **Risk/Return:**                                         | rr_RiskReturnAbstract    |                                                                                                                                                                                                                 |
| Registrant Name                                          | dei_EntityRegistrantName | Fidelity Rutland Square Trust II                                                                                                                                                                                     |
| Prospectus Date                                          | rr_ProspectusDate        | Jul. 30,  2015                                                                                                                                                                                                       |
| Strategic | Strategic Advisers Growth Multi-Manager Fund |                          |                                                                                                                                                                                                                 |
| **Risk/Return:**                                         | rr_RiskReturnAbstract    |                                                                                                                                                                                                                 |
| Supplement [Text Block]                                  | frst_SupplementTextBlock | **Supplement to the Strategic Advisers® Growth Multi-Manager Fund July 30, 2015 Prospectus***Effective October 1, 2015, the fund changed its classification from a non-diversified fund to a diversified fund.* |

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The exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC.
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| X                                                                                                                                 |
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