| Label                                             | **Element**              | Value                                                                                                                                                                                                                                  |
|---------------------------------------------------|--------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| **Risk/Return:**                                  | rr_RiskReturnAbstract    |                                                                                                                                                                                                                                   |
| Registrant Name                                   | dei_EntityRegistrantName | Fidelity Rutland Square Trust II                                                                                                                                                                                                       |
| Prospectus Date                                   | rr_ProspectusDate        | Jul. 30,  2015                                                                                                                                                                                                                         |
| L N | Strategic Advisers Value Multi-Manager Fund |                          |                                                                                                                                                                                                                                   |
| **Risk/Return:**                                  | rr_RiskReturnAbstract    |                                                                                                                                                                                                                                   |
| Supplement [Text Block]                           | frst_SupplementTextBlock | **Supplement to  Strategic Advisers® Value Multi-Manager Fund  Class L and Class N 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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| - Definition
The date of the prospectus.
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| X                                                                                                                                 |
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