Shareholder Report, Holdings (Details)	May 31, 2025
C000222038 \| U.S. Treasury Notes
Holdings [Line Items]
Percent of Net Asset Value	12.60%
C000222038 \| Federal National Mortgage Assn.
Holdings [Line Items]
Percent of Net Asset Value	4.20%
C000222038 \| Federal Home Loan Mortgage
Holdings [Line Items]
Percent of Net Asset Value	2.10%
C000222038 \| U.S. Treasury Inflation-Indexed Notes
Holdings [Line Items]
Percent of Net Asset Value	1.00%
C000222038 \| Progress Residential
Holdings [Line Items]
Percent of Net Asset Value	0.90%
C000222038 \| General Motors Financial
Holdings [Line Items]
Percent of Net Asset Value	0.80%
C000222038 \| Barclays
Holdings [Line Items]
Percent of Net Asset Value	0.80%
C000222038 \| Societe Generale
Holdings [Line Items]
Percent of Net Asset Value	0.70%
C000222038 \| Wells Fargo
Holdings [Line Items]
Percent of Net Asset Value	0.70%
C000222038 \| SMB Private Education Loan Trust
Holdings [Line Items]
Percent of Net Asset Value	0.70%
C000222038 \| Corporate Bonds
Holdings [Line Items]
Percent of Net Asset Value	40.00%
C000222038 \| Asset-Backed Securities
Holdings [Line Items]
Percent of Net Asset Value	24.80%
C000222038 \| U.S. Government Agency Obligations (Excluding Mortgage-Backed)
Holdings [Line Items]
Percent of Net Asset Value	13.60%
C000222038 \| Non-U.S. Government Mortgage-Backed Securities
Holdings [Line Items]
Percent of Net Asset Value	7.40%
C000222038 \| U.S. Government & Agency Mortgage-Backed Securities
Holdings [Line Items]
Percent of Net Asset Value	7.20%
C000222038 \| Commercial Paper
Holdings [Line Items]
Percent of Net Asset Value	2.40%
C000222038 \| Foreign Government Obligations & Municipalities
Holdings [Line Items]
Percent of Net Asset Value	2.10%
C000222038 \| Bank Loans
Holdings [Line Items]
Percent of Net Asset Value	1.10%
C000222038 \| Other Holdings Grouping
Holdings [Line Items]
Percent of Net Asset Value	1.40%
C000222039 \| U.S. Treasury Notes
Holdings [Line Items]
Percent of Net Asset Value	12.60%
C000222039 \| Federal National Mortgage Assn.
Holdings [Line Items]
Percent of Net Asset Value	4.20%
C000222039 \| Federal Home Loan Mortgage
Holdings [Line Items]
Percent of Net Asset Value	2.10%
C000222039 \| U.S. Treasury Inflation-Indexed Notes
Holdings [Line Items]
Percent of Net Asset Value	1.00%
C000222039 \| Progress Residential
Holdings [Line Items]
Percent of Net Asset Value	0.90%
C000222039 \| General Motors Financial
Holdings [Line Items]
Percent of Net Asset Value	0.80%
C000222039 \| Barclays
Holdings [Line Items]
Percent of Net Asset Value	0.80%
C000222039 \| Societe Generale
Holdings [Line Items]
Percent of Net Asset Value	0.70%
C000222039 \| Wells Fargo
Holdings [Line Items]
Percent of Net Asset Value	0.70%
C000222039 \| SMB Private Education Loan Trust
Holdings [Line Items]
Percent of Net Asset Value	0.70%
C000222039 \| Corporate Bonds
Holdings [Line Items]
Percent of Net Asset Value	40.00%
C000222039 \| Asset-Backed Securities
Holdings [Line Items]
Percent of Net Asset Value	24.80%
C000222039 \| U.S. Government Agency Obligations (Excluding Mortgage-Backed)
Holdings [Line Items]
Percent of Net Asset Value	13.60%
C000222039 \| Non-U.S. Government Mortgage-Backed Securities
Holdings [Line Items]
Percent of Net Asset Value	7.40%
C000222039 \| U.S. Government & Agency Mortgage-Backed Securities
Holdings [Line Items]
Percent of Net Asset Value	7.20%
C000222039 \| Commercial Paper
Holdings [Line Items]
Percent of Net Asset Value	2.40%
C000222039 \| Foreign Government Obligations & Municipalities
Holdings [Line Items]
Percent of Net Asset Value	2.10%
C000222039 \| Bank Loans
Holdings [Line Items]
Percent of Net Asset Value	1.10%
C000222039 \| Other Holdings Grouping
Holdings [Line Items]
Percent of Net Asset Value	1.40%