Shareholder Report, Line Graph (Details) - USD ($)	12 Months Ended	48 Months Ended	72 Months Ended	96 Months Ended	120 Months Ended	132 Months Ended
	Aug. 31, 2025	Aug. 31, 2025	Aug. 31, 2025	Aug. 31, 2025	Aug. 31, 2025	Aug. 31, 2025
C000205020_LG_ClassMember_8YRMember
Account Value [Line Items]
Line Graph and Table Measure Name				<span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class Z</span>
C000205020_ClassMember_AsOf_2018Member
Account Value [Line Items]
Accumulated Value	$ 10,000
C000205020_ClassMember_AsOf_2019Member
Account Value [Line Items]
Accumulated Value	10,450
C000205020_ClassMember_AsOf_2020Member
Account Value [Line Items]
Accumulated Value	10,858
C000205020_ClassMember_AsOf_2021Member
Account Value [Line Items]
Accumulated Value	10,923
C000205020_ClassMember_AsOf_2022Member
Account Value [Line Items]
Accumulated Value	10,475
C000205020_ClassMember_AsOf_2023Member
Account Value [Line Items]
Accumulated Value	10,725
C000205020_ClassMember_AsOf_2024Member
Account Value [Line Items]
Accumulated Value	11,439
C000205020_ClassMember_AsOf_2025Member
Account Value [Line Items]
Accumulated Value	12,004
C000205020_LG_1_AdditionalIndexMember_8YRMember
Account Value [Line Items]
Line Graph and Table Measure Name				<span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. 1-3 Year Government/Credit Bond Index</span>
C000205020_1_AdditionalIndexMember_AsOf_2018Member
Account Value [Line Items]
Accumulated Value	10,000
C000205020_1_AdditionalIndexMember_AsOf_2019Member
Account Value [Line Items]
Accumulated Value	10,467
C000205020_1_AdditionalIndexMember_AsOf_2020Member
Account Value [Line Items]
Accumulated Value	10,851
C000205020_1_AdditionalIndexMember_AsOf_2021Member
Account Value [Line Items]
Accumulated Value	10,893
C000205020_1_AdditionalIndexMember_AsOf_2022Member
Account Value [Line Items]
Accumulated Value	10,460
C000205020_1_AdditionalIndexMember_AsOf_2023Member
Account Value [Line Items]
Accumulated Value	10,623
C000205020_1_AdditionalIndexMember_AsOf_2024Member
Account Value [Line Items]
Accumulated Value	11,288
C000205020_1_AdditionalIndexMember_AsOf_2025Member
Account Value [Line Items]
Accumulated Value	11,811
C000205020_LG_2_AdditionalIndexMember_8YRMember
Account Value [Line Items]
Line Graph and Table Measure Name				<span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Aggregate Bond Index</span>
C000205020_2_AdditionalIndexMember_AsOf_2018Member
Account Value [Line Items]
Accumulated Value	10,000
C000205020_2_AdditionalIndexMember_AsOf_2019Member
Account Value [Line Items]
Accumulated Value	11,086
C000205020_2_AdditionalIndexMember_AsOf_2020Member
Account Value [Line Items]
Accumulated Value	11,804
C000205020_2_AdditionalIndexMember_AsOf_2021Member
Account Value [Line Items]
Accumulated Value	11,794
C000205020_2_AdditionalIndexMember_AsOf_2022Member
Account Value [Line Items]
Accumulated Value	10,436
C000205020_2_AdditionalIndexMember_AsOf_2023Member
Account Value [Line Items]
Accumulated Value	10,311
C000205020_2_AdditionalIndexMember_AsOf_2024Member
Account Value [Line Items]
Accumulated Value	11,064
C000205020_2_AdditionalIndexMember_AsOf_2025Member
Account Value [Line Items]
Accumulated Value	11,411
C000234194_LG_ClassMember_4YRMember
Account Value [Line Items]
Line Graph and Table Measure Name		<span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class I</span>
C000234194_ClassMember_AsOf_2022Member
Account Value [Line Items]
Accumulated Value	10,000
C000234194_ClassMember_AsOf_2023Member
Account Value [Line Items]
Accumulated Value	9,270
C000234194_ClassMember_AsOf_2024Member
Account Value [Line Items]
Accumulated Value	9,317
C000234194_ClassMember_AsOf_2025Member
Account Value [Line Items]
Accumulated Value	10,049
C000234194_LG_1_AdditionalIndexMember_4YRMember
Account Value [Line Items]
Line Graph and Table Measure Name		<span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Aggregate Bond Index</span>
C000234194_1_AdditionalIndexMember_AsOf_2022Member
Account Value [Line Items]
Accumulated Value	10,000
C000234194_1_AdditionalIndexMember_AsOf_2023Member
Account Value [Line Items]
Accumulated Value	9,301
C000234194_1_AdditionalIndexMember_AsOf_2024Member
Account Value [Line Items]
Accumulated Value	9,190
C000234194_1_AdditionalIndexMember_AsOf_2025Member
Account Value [Line Items]
Accumulated Value	9,861
C000019121_LG_ClassMember_11YRMember
Account Value [Line Items]
Line Graph and Table Measure Name						<span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class A</span>
C000019121_ClassMember_AsOf_2015Member
Account Value [Line Items]
Accumulated Value	9,600
C000019121_ClassMember_AsOf_2016Member
Account Value [Line Items]
Accumulated Value	10,200
C000019121_ClassMember_AsOf_2017Member
Account Value [Line Items]
Accumulated Value	10,306
C000019121_ClassMember_AsOf_2018Member
Account Value [Line Items]
Accumulated Value	10,177
C000019121_ClassMember_AsOf_2019Member
Account Value [Line Items]
Accumulated Value	11,206
C000019121_ClassMember_AsOf_2020Member
Account Value [Line Items]
Accumulated Value	12,136
C000019121_ClassMember_AsOf_2021Member
Account Value [Line Items]
Accumulated Value	12,244
C000019121_ClassMember_AsOf_2022Member
Account Value [Line Items]
Accumulated Value	10,785
C000019121_ClassMember_AsOf_2023Member
Account Value [Line Items]
Accumulated Value	10,683
C000019121_ClassMember_AsOf_2024Member
Account Value [Line Items]
Accumulated Value	11,485
C000019121_ClassMember_AsOf_2025Member
Account Value [Line Items]
Accumulated Value	11,828
C000019121_LG_1_AdditionalIndexMember_11YRMember
Account Value [Line Items]
Line Graph and Table Measure Name						<span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Aggregate Bond Index</span>
C000019121_1_AdditionalIndexMember_AsOf_2015Member
Account Value [Line Items]
Accumulated Value	10,000
C000019121_1_AdditionalIndexMember_AsOf_2016Member
Account Value [Line Items]
Accumulated Value	10,597
C000019121_1_AdditionalIndexMember_AsOf_2017Member
Account Value [Line Items]
Accumulated Value	10,649
C000019121_1_AdditionalIndexMember_AsOf_2018Member
Account Value [Line Items]
Accumulated Value	10,537
C000019121_1_AdditionalIndexMember_AsOf_2019Member
Account Value [Line Items]
Accumulated Value	11,609
C000019121_1_AdditionalIndexMember_AsOf_2020Member
Account Value [Line Items]
Accumulated Value	12,360
C000019121_1_AdditionalIndexMember_AsOf_2021Member
Account Value [Line Items]
Accumulated Value	12,350
C000019121_1_AdditionalIndexMember_AsOf_2022Member
Account Value [Line Items]
Accumulated Value	10,928
C000019121_1_AdditionalIndexMember_AsOf_2023Member
Account Value [Line Items]
Accumulated Value	10,797
C000019121_1_AdditionalIndexMember_AsOf_2024Member
Account Value [Line Items]
Accumulated Value	11,585
C000019121_1_AdditionalIndexMember_AsOf_2025Member
Account Value [Line Items]
Accumulated Value	11,949
C000048836_LG_ClassMember_11YRMember
Account Value [Line Items]
Line Graph and Table Measure Name						<span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Fidelity® Intermediate Bond Fund</span>
C000048836_ClassMember_AsOf_2015Member
Account Value [Line Items]
Accumulated Value	10,000
C000048836_ClassMember_AsOf_2016Member
Account Value [Line Items]
Accumulated Value	10,453
C000048836_ClassMember_AsOf_2017Member
Account Value [Line Items]
Accumulated Value	10,569
C000048836_ClassMember_AsOf_2018Member
Account Value [Line Items]
Accumulated Value	10,457
C000048836_ClassMember_AsOf_2019Member
Account Value [Line Items]
Accumulated Value	11,312
C000048836_ClassMember_AsOf_2020Member
Account Value [Line Items]
Accumulated Value	12,011
C000048836_ClassMember_AsOf_2021Member
Account Value [Line Items]
Accumulated Value	12,115
C000048836_ClassMember_AsOf_2022Member
Account Value [Line Items]
Accumulated Value	11,077
C000048836_ClassMember_AsOf_2023Member
Account Value [Line Items]
Accumulated Value	11,159
C000048836_ClassMember_AsOf_2024Member
Account Value [Line Items]
Accumulated Value	11,972
C000048836_ClassMember_AsOf_2025Member
Account Value [Line Items]
Accumulated Value	12,541
C000048836_LG_1_AdditionalIndexMember_11YRMember
Account Value [Line Items]
Line Graph and Table Measure Name						<span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Intermediate Government/Credit Bond Index</span>
C000048836_1_AdditionalIndexMember_AsOf_2015Member
Account Value [Line Items]
Accumulated Value	10,000
C000048836_1_AdditionalIndexMember_AsOf_2016Member
Account Value [Line Items]
Accumulated Value	10,407
C000048836_1_AdditionalIndexMember_AsOf_2017Member
Account Value [Line Items]
Accumulated Value	10,492
C000048836_1_AdditionalIndexMember_AsOf_2018Member
Account Value [Line Items]
Accumulated Value	10,386
C000048836_1_AdditionalIndexMember_AsOf_2019Member
Account Value [Line Items]
Accumulated Value	11,230
C000048836_1_AdditionalIndexMember_AsOf_2020Member
Account Value [Line Items]
Accumulated Value	11,898
C000048836_1_AdditionalIndexMember_AsOf_2021Member
Account Value [Line Items]
Accumulated Value	11,917
C000048836_1_AdditionalIndexMember_AsOf_2022Member
Account Value [Line Items]
Accumulated Value	10,940
C000048836_1_AdditionalIndexMember_AsOf_2023Member
Account Value [Line Items]
Accumulated Value	11,000
C000048836_1_AdditionalIndexMember_AsOf_2024Member
Account Value [Line Items]
Accumulated Value	11,782
C000048836_1_AdditionalIndexMember_AsOf_2025Member
Account Value [Line Items]
Accumulated Value	12,336
C000048836_LG_2_AdditionalIndexMember_11YRMember
Account Value [Line Items]
Line Graph and Table Measure Name						<span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Aggregate Bond Index</span>
C000048836_2_AdditionalIndexMember_AsOf_2015Member
Account Value [Line Items]
Accumulated Value	10,000
C000048836_2_AdditionalIndexMember_AsOf_2016Member
Account Value [Line Items]
Accumulated Value	10,597
C000048836_2_AdditionalIndexMember_AsOf_2017Member
Account Value [Line Items]
Accumulated Value	10,649
C000048836_2_AdditionalIndexMember_AsOf_2018Member
Account Value [Line Items]
Accumulated Value	10,537
C000048836_2_AdditionalIndexMember_AsOf_2019Member
Account Value [Line Items]
Accumulated Value	11,609
C000048836_2_AdditionalIndexMember_AsOf_2020Member
Account Value [Line Items]
Accumulated Value	12,360
C000048836_2_AdditionalIndexMember_AsOf_2021Member
Account Value [Line Items]
Accumulated Value	12,350
C000048836_2_AdditionalIndexMember_AsOf_2022Member
Account Value [Line Items]
Accumulated Value	10,928
C000048836_2_AdditionalIndexMember_AsOf_2023Member
Account Value [Line Items]
Accumulated Value	10,797
C000048836_2_AdditionalIndexMember_AsOf_2024Member
Account Value [Line Items]
Accumulated Value	11,585
C000048836_2_AdditionalIndexMember_AsOf_2025Member
Account Value [Line Items]
Accumulated Value	11,949
C000234192_LG_ClassMember_4YRMember
Account Value [Line Items]
Line Graph and Table Measure Name		<span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class C</span>
C000234192_ClassMember_AsOf_2022Member
Account Value [Line Items]
Accumulated Value	10,000
C000234192_ClassMember_AsOf_2023Member
Account Value [Line Items]
Accumulated Value	9,210
C000234192_ClassMember_AsOf_2024Member
Account Value [Line Items]
Accumulated Value	9,174
C000234192_ClassMember_AsOf_2025Member
Account Value [Line Items]
Accumulated Value	9,797
C000234192_LG_1_AdditionalIndexMember_4YRMember
Account Value [Line Items]
Line Graph and Table Measure Name		<span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Aggregate Bond Index</span>
C000234192_1_AdditionalIndexMember_AsOf_2022Member
Account Value [Line Items]
Accumulated Value	10,000
C000234192_1_AdditionalIndexMember_AsOf_2023Member
Account Value [Line Items]
Accumulated Value	9,301
C000234192_1_AdditionalIndexMember_AsOf_2024Member
Account Value [Line Items]
Accumulated Value	9,190
C000234192_1_AdditionalIndexMember_AsOf_2025Member
Account Value [Line Items]
Accumulated Value	9,861
C000019124_LG_ClassMember_11YRMember
Account Value [Line Items]
Line Graph and Table Measure Name						<span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class M</span>
C000019124_ClassMember_AsOf_2015Member
Account Value [Line Items]
Accumulated Value	9,600
C000019124_ClassMember_AsOf_2016Member
Account Value [Line Items]
Accumulated Value	10,196
C000019124_ClassMember_AsOf_2017Member
Account Value [Line Items]
Accumulated Value	10,298
C000019124_ClassMember_AsOf_2018Member
Account Value [Line Items]
Accumulated Value	10,169
C000019124_ClassMember_AsOf_2019Member
Account Value [Line Items]
Accumulated Value	11,194
C000019124_ClassMember_AsOf_2020Member
Account Value [Line Items]
Accumulated Value	12,123
C000019124_ClassMember_AsOf_2021Member
Account Value [Line Items]
Accumulated Value	12,218
C000019124_ClassMember_AsOf_2022Member
Account Value [Line Items]
Accumulated Value	10,763
C000019124_ClassMember_AsOf_2023Member
Account Value [Line Items]
Accumulated Value	10,661
C000019124_ClassMember_AsOf_2024Member
Account Value [Line Items]
Accumulated Value	11,462
C000019124_ClassMember_AsOf_2025Member
Account Value [Line Items]
Accumulated Value	11,821
C000019124_LG_1_AdditionalIndexMember_11YRMember
Account Value [Line Items]
Line Graph and Table Measure Name						<span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Aggregate Bond Index</span>
C000019124_1_AdditionalIndexMember_AsOf_2015Member
Account Value [Line Items]
Accumulated Value	10,000
C000019124_1_AdditionalIndexMember_AsOf_2016Member
Account Value [Line Items]
Accumulated Value	10,597
C000019124_1_AdditionalIndexMember_AsOf_2017Member
Account Value [Line Items]
Accumulated Value	10,649
C000019124_1_AdditionalIndexMember_AsOf_2018Member
Account Value [Line Items]
Accumulated Value	10,537
C000019124_1_AdditionalIndexMember_AsOf_2019Member
Account Value [Line Items]
Accumulated Value	11,609
C000019124_1_AdditionalIndexMember_AsOf_2020Member
Account Value [Line Items]
Accumulated Value	12,360
C000019124_1_AdditionalIndexMember_AsOf_2021Member
Account Value [Line Items]
Accumulated Value	12,350
C000019124_1_AdditionalIndexMember_AsOf_2022Member
Account Value [Line Items]
Accumulated Value	10,928
C000019124_1_AdditionalIndexMember_AsOf_2023Member
Account Value [Line Items]
Accumulated Value	10,797
C000019124_1_AdditionalIndexMember_AsOf_2024Member
Account Value [Line Items]
Accumulated Value	11,585
C000019124_1_AdditionalIndexMember_AsOf_2025Member
Account Value [Line Items]
Accumulated Value	11,949
C000200823_LG_ClassMember_8YRMember
Account Value [Line Items]
Line Graph and Table Measure Name				<span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Fidelity Flex® Conservative Income Bond Fund</span>
C000200823_ClassMember_AsOf_2018Member
Account Value [Line Items]
Accumulated Value	10,000
C000200823_ClassMember_AsOf_2019Member
Account Value [Line Items]
Accumulated Value	10,066
C000200823_ClassMember_AsOf_2020Member
Account Value [Line Items]
Accumulated Value	10,348
C000200823_ClassMember_AsOf_2021Member
Account Value [Line Items]
Accumulated Value	10,565
C000200823_ClassMember_AsOf_2022Member
Account Value [Line Items]
Accumulated Value	10,614
C000200823_ClassMember_AsOf_2023Member
Account Value [Line Items]
Accumulated Value	10,637
C000200823_ClassMember_AsOf_2024Member
Account Value [Line Items]
Accumulated Value	11,153
C000200823_ClassMember_AsOf_2025Member
Account Value [Line Items]
Accumulated Value	11,835
C000200823_LG_1_AdditionalIndexMember_8YRMember
Account Value [Line Items]
Line Graph and Table Measure Name				<span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. 3-6 Month Treasury Bill Index</span>
C000200823_1_AdditionalIndexMember_AsOf_2018Member
Account Value [Line Items]
Accumulated Value	10,000
C000200823_1_AdditionalIndexMember_AsOf_2019Member
Account Value [Line Items]
Accumulated Value	10,050
C000200823_1_AdditionalIndexMember_AsOf_2020Member
Account Value [Line Items]
Accumulated Value	10,302
C000200823_1_AdditionalIndexMember_AsOf_2021Member
Account Value [Line Items]
Accumulated Value	10,457
C000200823_1_AdditionalIndexMember_AsOf_2022Member
Account Value [Line Items]
Accumulated Value	10,466
C000200823_1_AdditionalIndexMember_AsOf_2023Member
Account Value [Line Items]
Accumulated Value	10,495
C000200823_1_AdditionalIndexMember_AsOf_2024Member
Account Value [Line Items]
Accumulated Value	10,945
C000200823_1_AdditionalIndexMember_AsOf_2025Member
Account Value [Line Items]
Accumulated Value	11,552
C000200823_LG_2_AdditionalIndexMember_8YRMember
Account Value [Line Items]
Line Graph and Table Measure Name				<span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Aggregate Bond Index</span>
C000200823_2_AdditionalIndexMember_AsOf_2018Member
Account Value [Line Items]
Accumulated Value	10,000
C000200823_2_AdditionalIndexMember_AsOf_2019Member
Account Value [Line Items]
Accumulated Value	10,054
C000200823_2_AdditionalIndexMember_AsOf_2020Member
Account Value [Line Items]
Accumulated Value	11,077
C000200823_2_AdditionalIndexMember_AsOf_2021Member
Account Value [Line Items]
Accumulated Value	11,794
C000200823_2_AdditionalIndexMember_AsOf_2022Member
Account Value [Line Items]
Accumulated Value	11,784
C000200823_2_AdditionalIndexMember_AsOf_2023Member
Account Value [Line Items]
Accumulated Value	10,427
C000200823_2_AdditionalIndexMember_AsOf_2024Member
Account Value [Line Items]
Accumulated Value	10,303
C000200823_2_AdditionalIndexMember_AsOf_2025Member
Account Value [Line Items]
Accumulated Value	11,055
C000234190_LG_ClassMember_4YRMember
Account Value [Line Items]
Line Graph and Table Measure Name		<span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class Z</span>
C000234190_ClassMember_AsOf_2022Member
Account Value [Line Items]
Accumulated Value	10,000
C000234190_ClassMember_AsOf_2023Member
Account Value [Line Items]
Accumulated Value	9,275
C000234190_ClassMember_AsOf_2024Member
Account Value [Line Items]
Accumulated Value	9,330
C000234190_ClassMember_AsOf_2025Member
Account Value [Line Items]
Accumulated Value	10,072
C000234190_LG_1_AdditionalIndexMember_4YRMember
Account Value [Line Items]
Line Graph and Table Measure Name		<span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Aggregate Bond Index</span>
C000234190_1_AdditionalIndexMember_AsOf_2022Member
Account Value [Line Items]
Accumulated Value	10,000
C000234190_1_AdditionalIndexMember_AsOf_2023Member
Account Value [Line Items]
Accumulated Value	9,301
C000234190_1_AdditionalIndexMember_AsOf_2024Member
Account Value [Line Items]
Accumulated Value	9,190
C000234190_1_AdditionalIndexMember_AsOf_2025Member
Account Value [Line Items]
Accumulated Value	9,861
C000019125_LG_ClassMember_11YRMember
Account Value [Line Items]
Line Graph and Table Measure Name						<span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class I</span>
C000019125_ClassMember_AsOf_2015Member
Account Value [Line Items]
Accumulated Value	10,000
C000019125_ClassMember_AsOf_2016Member
Account Value [Line Items]
Accumulated Value	10,653
C000019125_ClassMember_AsOf_2017Member
Account Value [Line Items]
Accumulated Value	10,793
C000019125_ClassMember_AsOf_2018Member
Account Value [Line Items]
Accumulated Value	10,687
C000019125_ClassMember_AsOf_2019Member
Account Value [Line Items]
Accumulated Value	11,797
C000019125_ClassMember_AsOf_2020Member
Account Value [Line Items]
Accumulated Value	12,810
C000019125_ClassMember_AsOf_2021Member
Account Value [Line Items]
Accumulated Value	12,942
C000019125_ClassMember_AsOf_2022Member
Account Value [Line Items]
Accumulated Value	11,432
C000019125_ClassMember_AsOf_2023Member
Account Value [Line Items]
Accumulated Value	11,352
C000019125_ClassMember_AsOf_2024Member
Account Value [Line Items]
Accumulated Value	12,234
C000019125_ClassMember_AsOf_2025Member
Account Value [Line Items]
Accumulated Value	12,649
C000019125_LG_1_AdditionalIndexMember_11YRMember
Account Value [Line Items]
Line Graph and Table Measure Name						<span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Aggregate Bond Index</span>
C000019125_1_AdditionalIndexMember_AsOf_2015Member
Account Value [Line Items]
Accumulated Value	10,000
C000019125_1_AdditionalIndexMember_AsOf_2016Member
Account Value [Line Items]
Accumulated Value	10,597
C000019125_1_AdditionalIndexMember_AsOf_2017Member
Account Value [Line Items]
Accumulated Value	10,649
C000019125_1_AdditionalIndexMember_AsOf_2018Member
Account Value [Line Items]
Accumulated Value	10,537
C000019125_1_AdditionalIndexMember_AsOf_2019Member
Account Value [Line Items]
Accumulated Value	11,609
C000019125_1_AdditionalIndexMember_AsOf_2020Member
Account Value [Line Items]
Accumulated Value	12,360
C000019125_1_AdditionalIndexMember_AsOf_2021Member
Account Value [Line Items]
Accumulated Value	12,350
C000019125_1_AdditionalIndexMember_AsOf_2022Member
Account Value [Line Items]
Accumulated Value	10,928
C000019125_1_AdditionalIndexMember_AsOf_2023Member
Account Value [Line Items]
Accumulated Value	10,797
C000019125_1_AdditionalIndexMember_AsOf_2024Member
Account Value [Line Items]
Accumulated Value	11,585
C000019125_1_AdditionalIndexMember_AsOf_2025Member
Account Value [Line Items]
Accumulated Value	11,949
C000019123_LG_ClassMember_11YRMember
Account Value [Line Items]
Line Graph and Table Measure Name						<span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class C</span>
C000019123_ClassMember_AsOf_2015Member
Account Value [Line Items]
Accumulated Value	10,000
C000019123_ClassMember_AsOf_2016Member
Account Value [Line Items]
Accumulated Value	10,557
C000019123_ClassMember_AsOf_2017Member
Account Value [Line Items]
Accumulated Value	10,586
C000019123_ClassMember_AsOf_2018Member
Account Value [Line Items]
Accumulated Value	10,361
C000019123_ClassMember_AsOf_2019Member
Account Value [Line Items]
Accumulated Value	11,320
C000019123_ClassMember_AsOf_2020Member
Account Value [Line Items]
Accumulated Value	12,164
C000019123_ClassMember_AsOf_2021Member
Account Value [Line Items]
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