| Standard label: | Auction Market Preferred Securities, Stock Series, Variable Interest Rate Earned |
| Name: | us-gaap:AuctionMarketPreferredSecuritiesStockSeriesVariableInterestRateEarned |
| Documentation: | The interest (or dividend) rates earned on action market preferred securities (on an annual basis or APY) for the period reported. |
| Object type: | cm:Concept |
| Data type: | Percent (num:percentItemType) |
| Period type: | For Period (duration) |
| Balance type: | (no balance type) |
| Abstract: | false |
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:AuctionMarketPreferredSecuritiesStockSeriesVariableInterestRateEarned |
| Label | Role | Language |
| Auction Market Preferred Securities, Stock Series, Variable Interest Rate Earned | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 210 10 S99 1 (SX 210.5-02(28)) | http://fasb.org/us-gaap/role/ref/legacyRef | 210 |
| FASB Accounting Standards Codification 505 10 50 3 | http://fasb.org/us-gaap/role/ref/legacyRef | 505 |