| Submission | Feb. 12, 2025 |
| Submission [Line Items] | |
| Central Index Key | 0000021175 |
| Registrant Name | CNA FINANCIAL CORP |
| Form Type | S-3 |
| Submission Type | S-3ASR |
| Fee Exhibit Type | EX-FILING FEES |
| Offerings | Feb. 12, 2025 |
| Offering: 1 | |
| Offering: | |
| Fee Previously Paid | false |
| Rule 457(r) | true |
| Security Type | Debt |
| Security Class Title | Senior Debt Securities |
| Fee Rate | 0.01531% |
| Offering Note | An indeterminate number and aggregate initial offering price of each identified class are being registered as may from time to time be sold at indeterminate prices, including an indeterminate number or amount of securities that may be issued upon the conversion, exchange, exercise or settlement of securities offered hereunder. Separate consideration may or may not be received for securities that are issuable upon conversion, exchange, exercise or settlement of other securities or that are represented by depositary shares or issued in purchase units. In reliance on and in accordance with Rules 456(b) and 457(r), the Registrant is deferring payment of all of the registration fees. |
| Offering: 2 | |
| Offering: | |
| Fee Previously Paid | false |
| Rule 457(r) | true |
| Security Type | Debt |
| Security Class Title | Subordinated Debt Securities |
| Fee Rate | 0.01531% |
| Offering Note | See Offering Note 1. |
| Offering: 3 | |
| Offering: | |
| Fee Previously Paid | false |
| Rule 457(r) | true |
| Security Type | Debt |
| Security Class Title | Subordinated Junior Debt Securities |
| Fee Rate | 0.01531% |
| Offering Note | See Offering Note 1. |
| Offering: 4 | |
| Offering: | |
| Fee Previously Paid | false |
| Rule 457(r) | true |
| Security Type | Equity |
| Security Class Title | Preferred Stock, no par value |
| Fee Rate | 0.01531% |
| Offering Note | See Offering Note 1. |
| Offering: 5 | |
| Offering: | |
| Fee Previously Paid | false |
| Rule 457(r) | true |
| Security Type | Equity |
| Security Class Title | Depositary Shares |
| Fee Rate | 0.01531% |
| Offering Note | Depositary shares will be evidenced by depositary receipts issued pursuant to a deposit agreement and will represent a fractional share or multiple shares of preferred stock. See Offering Note 1. |
| Offering: 6 | |
| Offering: | |
| Fee Previously Paid | false |
| Rule 457(r) | true |
| Security Type | Equity |
| Security Class Title | Common Stock, 2.50 par value |
| Fee Rate | 0.01531% |
| Offering Note | See Offering Note 1. |
| Offering: 7 | |
| Offering: | |
| Fee Previously Paid | false |
| Rule 457(r) | true |
| Security Type | Other |
| Security Class Title | Warrants |
| Fee Rate | 0.01531% |
| Offering Note | Warrants may represent rights to purchase debt securities, depositary shares or shares of preferred stock or common stock registered under this registration statement. See Offering Note 1. |
| Offering: 8 | |
| Offering: | |
| Fee Previously Paid | false |
| Rule 457(r) | true |
| Security Type | Other |
| Security Class Title | Purchase Contracts |
| Fee Rate | 0.01531% |
| Offering Note | Purchase contracts may be issued separately or as purchase units. See Offering Note 1. |
| Offering: 9 | |
| Offering: | |
| Fee Previously Paid | false |
| Rule 457(r) | true |
| Security Type | Other |
| Security Class Title | Purchase Units |
| Fee Rate | 0.01531% |
| Offering Note | Purchase units may consist of a purchase contract and any of the debt securities registered under this registration statement or debt obligations of third parties, including U.S. treasury securities, securing the holders' obligations to purchase the applicable purchase contract securities under the purchase contract. See Offering Note 1. |
| Fees Summary | Feb. 12, 2025 USD ($) |
| Fees Summary [Line Items] | |
| Total Offering | $ 0 |
| Previously Paid Amount | 0 |
| Total Fee Amount | 0 |
| Total Offset Amount | 0 |
| Net Fee | $ 0 |
