Fidelity Oxford Street Trust II N-CSR20 Sep 24Certified annual shareholder report (management investment company)Financial data

Company Profile

Form N-CSR Cover

Form N-CSR Cover	12 Months Ended
Form N-CSR Cover	Jul. 31, 2024
Shareholder Report [Line Items]
Document Type	N-CSR
Amendment Flag	false
Registrant Name	Fidelity Oxford Street Trust II
Entity Central Index Key	0001586462
Entity Investment Company Type	N-1A
Document Period End Date	Jul. 31, 2024

Shareholder Report

Shareholder Report	12 Months Ended
Shareholder Report	Jul. 31, 2024 USD ($) shares
Shareholder Report [Line Items]
Document Type	N-CSR
Amendment Flag	false
Registrant Name	Fidelity Oxford Street Trust II
Entity Central Index Key	0001586462
Entity Investment Company Type	N-1A
Document Period End Date	Jul. 31, 2024
Fidelity Commodity Strategy Central Fund
Shareholder Report [Line Items]
Fund Name	Fidelity® Commodity Strategy Central Fund
Class Name	Fidelity® Commodity Strategy Central Fund
No Trading Symbol Flag	true
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity® Commodity Strategy Central Fund for the period 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 fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-544-8544.
Additional Information Phone Number	1-800-544-8544
Additional Information Website	fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block]	What were your Fund costs for the last year? (based on hypothetical $10,000 investment) FUND COST (PREVIOUS YEAR) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Fidelity® Commodity Strategy Central Fund $ 0.01 %
Expenses Paid, Amount	$ 1
Expense Ratio, Percent	0.01%
Factors Affecting Performance [Text Block]	What affected the Fund's performance this period? • • • • •
Performance Past Does Not Indicate Future [Text]	The Fund's past performance is not a good predictor of the Fund's future performance.</span>" id="sjs-B24"><span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">The Fund's past performance is not a good predictor of the Fund's future performance.</span>
Line Graph [Table Text Block]	How did the Fund perform over the past 10 years? CUMULATIVE PERFORMANCE July 31, 2014 through July 31, 2024. Initial investment of $10,000. Fidelity® Commodity Strategy Central Fund $10,000 $7,158 $6,587 $6,704 $7,050 $6,572 $5,888 $8,196 $10,462 $9,532 $9,192 Bloomberg Commodity Index $10,000 $7,177 $6,604 $6,655 $6,837 $6,470 $5,689 $7,980 $10,153 $9,353 $8,869 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024
Average Annual Return [Table Text Block]	AVERAGE ANNUAL TOTAL RETURNS: 1 Year 5 Year 10 Year Fidelity® Commodity Strategy Central Fund -3.57% 6.94% -0.84% Bloomberg Commodity Index -5.17% 6.51% -1.19% Visit www.fidelity.com for more recent performance information. The Fund's past performance is not a good predictor of the Fund's future performance. The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares.
No Deduction of Taxes [Text Block]	The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares.
Net Assets	$ 223,724,004
Holdings Count \| shares	44
Advisory Fees Paid, Amount	$ 0
Investment Company Portfolio Turnover	0%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of July 31, 2024) KEY FACTS Fund Size $ Number of Holdings 44 Total Advisory Fee $ Portfolio Turnover 0 %
Holdings [Text Block]	Energy 29.7 Agriculture 27.4 Precious Metals 22.5 Industrial Metals 14.0 Livestock 6.4 COMMODITY SECTOR DIVERSIFICATION (% of Fund's net assets) DERIVATIVE EXPOSURE (% of Fund's net assets) Futures Contracts 99.9 Futures Contracts 49.9 Short-Term Investments and Net Other Assets (Liabilities) 50.1 ASSET ALLOCATION (% of Fund's total exposure)

Shareholder Report, Line Graph

Shareholder Report, Line Graph (Details) - USD ($)

12 Months Ended

60 Months Ended

120 Months Ended

132 Months Ended

Jul. 31, 2024

Jul. 31, 2023

Jul. 31, 2022

Jul. 31, 2021

Jul. 31, 2020

Jul. 31, 2019

Jul. 31, 2018

Jul. 31, 2017

Jul. 31, 2016

Jul. 31, 2015

Jul. 31, 2014

C000133805_0_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

(5.17%)

C000133805_0_BBIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

6.51%

C000133805_0_BBIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

(1.19%)

C000133805_LG_ClassMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Fidelity® Commodity Strategy Central Fund" id="sjs-E14">Fidelity® Commodity Strategy Central Fund

C000133805_ClassMember_AsOf_2014Member

Account Value [Line Items]

Account Value

$ 10,000

C000133805_ClassMember_AsOf_2015Member

Account Value [Line Items]

Account Value

$ 7,158

C000133805_ClassMember_AsOf_2016Member

Account Value [Line Items]

Account Value

$ 6,587

C000133805_ClassMember_AsOf_2017Member

Account Value [Line Items]

Account Value

$ 6,704

C000133805_ClassMember_AsOf_2018Member

Account Value [Line Items]

Account Value

$ 7,050

C000133805_ClassMember_AsOf_2019Member

Account Value [Line Items]

Account Value

$ 6,572

C000133805_ClassMember_AsOf_2020Member

Account Value [Line Items]

Account Value

$ 5,888

C000133805_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

$ 8,196

C000133805_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

$ 10,462

C000133805_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

$ 9,532

C000133805_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 9,192

C000133805_LG_1_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg Commodity Index" id="sjs-E50">Bloomberg Commodity Index

C000133805_1_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

$ 10,000

C000133805_1_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

$ 7,177

C000133805_1_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

$ 6,604

C000133805_1_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

$ 6,655

C000133805_1_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

$ 6,837

C000133805_1_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

$ 6,470

C000133805_1_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

$ 5,689

C000133805_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

$ 7,980

C000133805_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

$ 10,153

C000133805_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

$ 9,353

C000133805_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 8,869

C000133805_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

(3.57%)

C000133805_NoLoadClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

6.94%

C000133805_NoLoadClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.84%)

Shareholder Report, Holdings (D

Shareholder Report, Holdings (Details) - Fidelity Commodity Strategy Central Fund	Jul. 31, 2024
MSPreciousMetalsSectorMember
Holdings [Line Items]
Percent of Net Asset Value	22.50%
MSIndustrialMetalsSectorMember
Holdings [Line Items]
Percent of Net Asset Value	14%
MSLivestockSectorMember
Holdings [Line Items]
Percent of Net Asset Value	6.40%
Agricultural Sector Member
Holdings [Line Items]
Percent of Net Asset Value	27.40%
Energy Sector
Holdings [Line Items]
Percent of Net Asset Value	29.70%
DEFuturesContractsMember
Holdings [Line Items]
Percent of Net Asset Value	99.90%
AAFuturesContractsMember
Holdings [Line Items]
Percent of Net Long Exposure	49.90%
AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Long Exposure	50.10%