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Pension and Postretirement Health and Life Benefits Pension and Postretirement Health and Life Benefits (Schedule of Fair Value of Plan Assets) (Details) (USD $) In Millions, unless otherwise specified | Dec. 31, 2013 | Dec. 31, 2012 | Dec. 31, 2011
--- | --- | --- | ---
Pension Plan, Defined Benefit [Member] |  |  |
US Government Securities | $ 74.2 | $ 89.8 |
Collective Trust - Money Market Funds | 19.4 | 16.5 |
Collective Trust - Bond Funds | 48.1 | 47.7 |
Collective Trust - Equity Funds | 423.1 | 397.4 |
Corporate Debt | 208.5 | 211.7 |
Municipal Bonds | 7.0 | 7.8 |
Mortgage and Asset-Backed Securities | 0 | 0.2 |
Fair Value of Investments by Hierarchy Level | 780.3 | 771.1 |
Accrued Interest Receivable | 4.0 | 3.8 |
Unsettled Transactions Receivable | (0.3) | (0.1) |
Defined Benefit Plan, Fair Value of Plan Assets | 784.0 | 774.8 | 727.8
Other Postretirement Benefit Plan, Defined Benefit [Member] |  |  |
Money Market Funds | 0.9 | 0.8 |
Bond Mutual Funds | 10.4 | 13.7 |
Equity Mutual Funds | 25.6 | 27.1 |
Fair Value of Investments by Hierarchy Level | 36.9 | 41.6 |
Defined Benefit Plan, Fair Value of Plan Assets | 36.9 | 41.6 | 45.1
Fair Value, Inputs, Level 1 [Member] | Pension Plan, Defined Benefit [Member] |  |  |
US Government Securities | 0 | 0 |
Collective Trust - Money Market Funds | 0 | 0 |
Collective Trust - Bond Funds | 0 | 0 |
Collective Trust - Equity Funds | 0 | 0 |
Corporate Debt | 0 | 0 |
Municipal Bonds | 0 | 0 |
Mortgage and Asset-Backed Securities | 0 | 0 |
Fair Value of Investments by Hierarchy Level | 0 | 0 |
Fair Value, Inputs, Level 1 [Member] | Other Postretirement Benefit Plan, Defined Benefit [Member] |  |  |
Money Market Funds | 0 | 0 |
Bond Mutual Funds | 10.4 | 13.7 |
Equity Mutual Funds | 25.6 | 27.1 |
Fair Value of Investments by Hierarchy Level | 36.0 | 40.8 |
Fair Value, Inputs, Level 2 [Member] | Pension Plan, Defined Benefit [Member] |  |  |
US Government Securities | 74.2 | 89.8 |
Collective Trust - Money Market Funds | 19.4 | 16.5 |
Collective Trust - Bond Funds | 48.1 | 47.7 |
Collective Trust - Equity Funds | 423.1 | 397.4 |
Corporate Debt | 208.5 | 211.1 |
Municipal Bonds | 7.0 | 7.8 |
Mortgage and Asset-Backed Securities | 0 | 0.2 |
Fair Value of Investments by Hierarchy Level | 780.3 | 770.5 |
Fair Value, Inputs, Level 2 [Member] | Other Postretirement Benefit Plan, Defined Benefit [Member] |  |  |
Money Market Funds | 0.9 | 0.8 |
Bond Mutual Funds | 0 | 0 |
Equity Mutual Funds | 0 | 0 |
Fair Value of Investments by Hierarchy Level | 0.9 | 0.8 |
Fair Value, Inputs, Level 3 [Member] | Pension Plan, Defined Benefit [Member] |  |  |
US Government Securities | 0 | 0 |
Collective Trust - Money Market Funds | 0 | 0 |
Collective Trust - Bond Funds | 0 | 0 |
Collective Trust - Equity Funds | 0 | 0 |
Corporate Debt |  | 0.6 |
Municipal Bonds | 0 | 0 |
Mortgage and Asset-Backed Securities | 0 | 0 |
Fair Value of Investments by Hierarchy Level | 0 | 0.6 |
Fair Value, Inputs, Level 3 [Member] | Other Postretirement Benefit Plan, Defined Benefit [Member] |  |  |
Money Market Funds | 0 | 0 |
Bond Mutual Funds | 0 | 0 |
Equity Mutual Funds | 0 | 0 |
Fair Value of Investments by Hierarchy Level | $ 0 | $ 0 |

X
- Definition Investments in notes or bonds that are collateralized by a specific group of underlying assets owned by the issuer of the notes or bonds which are short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Cash Equivalents -URI http://asc.fasb.org/extlink&oid=6507016 + Details
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- Definition Assets, usually stocks, bonds, and other investments, that have been segregated and restricted (usually in a trust) to provide benefits, at their fair value as of the measurement date. Plan assets include amounts contributed by the employer (and by employees for a contributory plan) and amounts earned from investing the contributions, less benefits paid. If a plan has liabilities other than for benefits, those non-benefit obligations may be considered as reductions of plan assets. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 30 -Section 35 -Paragraph 50 -URI http://asc.fasb.org/extlink&oid=29635418&loc=d3e12355-114930 + Details
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- Definition Investment in short-term money-market instruments (such as commercial paper, banker's acceptances, repurchase agreements, government securities, certificates of deposit, and so forth) which are highly liquid (that is, readily convertible to known amounts of cash) and so near their maturity that they present an insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify as cash equivalents by definition. Original maturity means an original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Cash Equivalents -URI http://asc.fasb.org/extlink&oid=6507016 + Details
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- Definition Bonds or similar securities issued by state, city, or local governments or the agencies operated by state, city, or local governments which are short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Cash Equivalents -URI http://asc.fasb.org/extlink&oid=6507016 + Details
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- Definition Debt (bills, notes or bonds) that are issued by the government of the United States which are short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Cash Equivalents -URI http://asc.fasb.org/extlink&oid=6507016 + Details
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- Definition Bond Mutual Funds + References No definition available. + Details
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- Definition Collective Trust Bond Funds + References No definition available. + Details
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- Definition Collective trust - equity funds + References No definition available. + Details
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