Summary of Significant Accounting Policies: FHLB Stock (Details) - USD ($)	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
FHLB, stock impairment charges	$ 0	$ 0
Minimum
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
FHLB, investment in capital stock, home loans (percent)	0.12%
FHLB, investment in capital stock, advances (percent)	4.00%