Shareholder Report, Average Annual Return (Details)	12 Months Ended	60 Months Ended	120 Months Ended
Shareholder Report, Average Annual Return (Details)	May 31, 2025	May 31, 2025	May 31, 2025
C000001854 [Member]
Average Annual Return [Line Items]
Line Graph and Table Measure Name	Bond Fund (Class A/JHNBX)
Average Annual Return, Percent	1.12%	(0.96%)	1.38%
C000001856 [Member]
Average Annual Return [Line Items]
Line Graph and Table Measure Name	Bond Fund (Class C/JHCBX)
Average Annual Return, Percent	3.59%	(0.85%)	1.09%
C000001857 [Member]
Average Annual Return [Line Items]
Line Graph and Table Measure Name	Bond Fund (Class I/JHBIX)
Average Annual Return, Percent	5.64%	0.15%	2.10%
C000153977 [Member]
Average Annual Return [Line Items]
Line Graph and Table Measure Name	Bond Fund (Class NAV)
Average Annual Return, Percent	5.76%	0.27%	2.22%
C000113488 [Member]
Average Annual Return [Line Items]
Line Graph and Table Measure Name	Bond Fund (Class R2/JHRBX)
Average Annual Return, Percent	5.15%	(0.25%)	1.70%
C000153978 [Member]
Average Annual Return [Line Items]
Line Graph and Table Measure Name	Bond Fund (Class R4/JBFRX)
Average Annual Return, Percent	5.49%	0.02%	1.97%
C000106442 [Member]
Average Annual Return [Line Items]
Line Graph and Table Measure Name	Bond Fund (Class R6/JHBSX)
Average Annual Return, Percent	5.67%	0.25%	2.22%
Without Sales Load [Member] \| C000001854 [Member]
Average Annual Return [Line Items]
Line Graph and Table Measure Name	Bond Fund (Class A/JHNBX)—excluding sales charge
Average Annual Return, Percent	5.32%	(0.15%)	1.80%
Without Sales Load [Member] \| C000001856 [Member]
Average Annual Return [Line Items]
Line Graph and Table Measure Name	Bond Fund (Class C/JHCBX)—excluding sales charge
Average Annual Return, Percent	4.59%	(0.85%)	1.09%
Bloomberg U S Aggregate Bond Index [Member]
Average Annual Return [Line Items]
Line Graph and Table Measure Name	Bloomberg U.S. Aggregate Bond Index
Average Annual Return, Percent	5.46%	(0.90%)	1.49%