Statutory Capital	9 Months Ended
Sep. 30, 2015
Statutory Capital [Abstract]
Statutory Capital	Statutory Capital Statutory Capital Requirements The insurance laws of 16 jurisdictions, including Wisconsin, our domiciliary state, require a mortgage insurer to maintain a minimum amount of statutory capital relative to the risk in force (or a similar measure) in order for the mortgage insurer to continue to write new business. We refer to these requirements as the “State Capital Requirements” and, together with the GSE Financial Requirements, the “Financial Requirements.” While they vary among jurisdictions, the most common State Capital Requirements allow for a maximum risk-to-capital ratio of 25 to 1. A risk-to-capital ratio will increase if (i) the percentage decrease in capital exceeds the percentage decrease in insured risk, or (ii) the percentage increase in capital is less than the percentage increase in insured risk. Wisconsin does not regulate capital by using a risk-to-capital measure but instead requires a minimum policyholder position (“MPP”). The “policyholder position” of a mortgage insurer is its net worth or surplus, contingency reserve and a portion of the reserves for unearned premiums. At September 30, 2015, MGIC’s risk-to-capital ratio was 12.3 to 1, below the maximum allowed by the jurisdictions with State Capital Requirements, and its policyholder position was $1.1 billion above the required MPP of $1.1 billion. In calculating our risk-to-capital ratio and MPP, we are allowed full credit for the risk ceded under our reinsurance transaction with a group of unaffiliated reinsurers. It is possible that under the revised State Capital Requirements discussed below, MGIC will not be allowed full credit for the risk ceded to the reinsurers. If MGIC is not allowed an agreed level of credit under either the State Capital Requirements or the PMIERs, MGIC may terminate the reinsurance agreement, without penalty. At this time, we expect MGIC to continue to comply with the current State Capital Requirements; however, you should read the rest of these financial statement footnotes for information about matters that could negatively affect such compliance. At September 30, 2015, the risk-to-capital ratio of our combined insurance operations (which includes reinsurance affiliates) was 13.6 to 1. Reinsurance agreements with affiliates permit MGIC to write insurance with a higher coverage percentage than it could on its own under certain state-specific requirements. A higher risk-to-capital ratio on a combined basis may indicate that, in order for MGIC to continue to utilize reinsurance agreements with its affiliates, unless a waiver of the State Capital Requirements of Wisconsin continues to be effective, additional capital contributions to the reinsurance affiliates could be needed. The NAIC previously announced that it plans to revise the minimum capital and surplus requirements for mortgage insurers that are provided for in its Mortgage Guaranty Insurance Model Act. A working group of state regulators is drafting the revisions, although no date has been established by which the NAIC must propose revisions to such requirements. Depending on the scope of revisions made by the NAIC, MGIC may be prevented from writing new business in the jurisdictions adopting such revisions. If MGIC fails to meet the State Capital Requirements of Wisconsin and is unable to obtain a waiver of them from the OCI, MGIC could be prevented from writing new business in all jurisdictions. If MGIC fails to meet the State Capital Requirements of a jurisdiction other than Wisconsin and is unable to obtain a waiver of them, MGIC could be prevented from writing new business in that particular jurisdiction. It is possible that regulatory action by one or more jurisdictions, including those that do not have specific State Capital Requirements, may prevent MGIC from continuing to write new insurance in such jurisdictions. If we are unable to write business in all jurisdictions, lenders may be unwilling to procure insurance from us anywhere. In addition, a lender’s assessment of the future ability of our insurance operations to meet the Financial Requirements may affect its willingness to procure insurance from us. A possible future failure by MGIC to meet the Financial Requirements will not necessarily mean that MGIC lacks sufficient resources to pay claims on its insurance liabilities. While we believe MGIC has sufficient claims paying resources to meet its claim obligations on its insurance in force on a timely basis, you should read the rest of these financial statement footnotes for information about matters that could negatively affect MGIC’s claims paying resources. Statement of Statutory Accounting Principles No. 101 (“SSAP No. 101”) became effective January 1, 2012 and prescribed new standards for determining the amount of deferred tax assets that can be recognized as admitted assets for determining statutory capital. Under a permitted practice effective September 30, 2012 the OCI approved MGIC to report its net deferred tax asset as an admitted asset in an amount not to exceed 10% of adjusted surplus as regards policyholders, notwithstanding any contrary provisions of SSAP No. 101. Net deferred tax assets of $138 million were included in MGIC’s statutory capital at December 31, 2014. Due to the deferred tax asset valuation allowance reversal as of September 30, 2015, MGIC no longer relies on the permitted practice and the deferred tax asset is admitted according to the stated provisions of SSAP No. 101. Under the stated provisions of SSAP No. 101, the admitted net deferred tax asset is 15% of adjusted surplus as regards policyholders. Net deferred tax assets of $211 million were included in MGIC's statutory capital as of September 30, 2015. See Note 1 – “Nature of Business and Basis of Presentation – Capital” for additional information regarding the capital standards of the GSEs.

Statutory Capital

Statutory Capital Requirements

The insurance laws of 16 jurisdictions, including Wisconsin, our domiciliary state, require a mortgage insurer to maintain a minimum amount of statutory capital relative to the risk in force (or a similar measure) in order for the mortgage insurer to continue to write new business. We refer to these requirements as the “State Capital Requirements” and, together with the GSE Financial Requirements, the “Financial Requirements.” While they vary among jurisdictions, the most common State Capital Requirements allow for a maximum risk-to-capital ratio of 25 to 1. A risk-to-capital ratio will increase if (i) the percentage decrease in capital exceeds the percentage decrease in insured risk, or (ii) the percentage increase in capital is less than the percentage increase in insured risk. Wisconsin does not regulate capital by using a risk-to-capital measure but instead requires a minimum policyholder position (“MPP”). The “policyholder position” of a mortgage insurer is its net worth or surplus, contingency reserve and a portion of the reserves for unearned premiums.

At September 30, 2015, MGIC’s risk-to-capital ratio was 12.3 to 1, below the maximum allowed by the jurisdictions with State Capital Requirements, and its policyholder position was $1.1 billion above the required MPP of $1.1 billion. In calculating our risk-to-capital ratio and MPP, we are allowed full credit for the risk ceded under our reinsurance transaction with a group of unaffiliated reinsurers. It is possible that under the revised State Capital Requirements discussed below, MGIC will not be allowed full credit for the risk ceded to the reinsurers. If MGIC is not allowed an agreed level of credit under either the State Capital Requirements or the PMIERs, MGIC may terminate the reinsurance agreement, without penalty. At this time, we expect MGIC to continue to comply with the current State Capital Requirements; however, you should read the rest of these financial statement footnotes for information about matters that could negatively affect such compliance.

At September 30, 2015, the risk-to-capital ratio of our combined insurance operations (which includes reinsurance affiliates) was 13.6 to 1. Reinsurance agreements with affiliates permit MGIC to write insurance with a higher coverage percentage than it could on its own under certain state-specific requirements. A higher risk-to-capital ratio on a combined basis may indicate that, in order for MGIC to continue to utilize reinsurance agreements with its affiliates, unless a waiver of the State Capital Requirements of Wisconsin continues to be effective, additional capital contributions to the reinsurance affiliates could be needed.

The NAIC previously announced that it plans to revise the minimum capital and surplus requirements for mortgage insurers that are provided for in its Mortgage Guaranty Insurance Model Act. A working group of state regulators is drafting the revisions, although no date has been established by which the NAIC must propose revisions to such requirements. Depending on the scope of revisions made by the NAIC, MGIC may be prevented from writing new business in the jurisdictions adopting such revisions.

If MGIC fails to meet the State Capital Requirements of Wisconsin and is unable to obtain a waiver of them from the OCI, MGIC could be prevented from writing new business in all jurisdictions. If MGIC fails to meet the State Capital Requirements of a jurisdiction other than Wisconsin and is unable to obtain a waiver of them, MGIC could be prevented from writing new business in that particular jurisdiction. It is possible that regulatory action by one or more jurisdictions, including those that do not have specific State Capital Requirements, may prevent MGIC from continuing to write new insurance in such jurisdictions.

If we are unable to write business in all jurisdictions, lenders may be unwilling to procure insurance from us anywhere. In addition, a lender’s assessment of the future ability of our insurance operations to meet the Financial Requirements may affect its willingness to procure insurance from us. A possible future failure by MGIC to meet the Financial Requirements will not necessarily mean that MGIC lacks sufficient resources to pay claims on its insurance liabilities. While we believe MGIC has sufficient claims paying resources to meet its claim obligations on its insurance in force on a timely basis, you should read the rest of these financial statement footnotes for information about matters that could negatively affect MGIC’s claims paying resources.

Statement of Statutory Accounting Principles No. 101 (“SSAP No. 101”) became effective January 1, 2012 and prescribed new standards for determining the amount of deferred tax assets that can be recognized as admitted assets for determining statutory capital. Under a permitted practice effective September 30, 2012 the OCI approved MGIC to report its net deferred tax asset as an admitted asset in an amount not to exceed 10% of adjusted surplus as regards policyholders, notwithstanding any contrary provisions of SSAP No. 101. Net deferred tax assets of $138 million were included in MGIC’s statutory capital at December 31, 2014. Due to the deferred tax asset valuation allowance reversal as of September 30, 2015, MGIC no longer relies on the permitted practice and the deferred tax asset is admitted according to the stated provisions of SSAP No. 101. Under the stated provisions of SSAP No. 101, the admitted net deferred tax asset is 15% of adjusted surplus as regards policyholders. Net deferred tax assets of $211 million were included in MGIC's statutory capital as of September 30, 2015.

See Note 1 – “Nature of Business and Basis of Presentation – Capital” for additional information regarding the capital standards of the GSEs.