Fair Value of Pension and Postretirement Plan Assets (Details) - USD ($) $ in Millions | Dec. 31, 2015 | Dec. 31, 2014 | Dec. 31, 2013 |
Pension Plan [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | $ 169 | $ 187 | $ 237 |
Pension Plan [Member] | Fair Value, Inputs, Level 1 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 17 | 32 | |
Pension Plan [Member] | Fair Value, Inputs, Level 2 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 152 | 155 | |
Pension Plan [Member] | Fair Value, Inputs, Level 3 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 0 | 0 | |
Pension Plan [Member] | Cash and Cash Equivalents [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 5 | 10 | |
Pension Plan [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 5 | 10 | |
Pension Plan [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 0 | 0 | |
Pension Plan [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 0 | 0 | |
Pension Plan [Member] | Domestic Equity Securities [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [1],[2] | 27 | 30 | |
Pension Plan [Member] | Domestic Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [1],[2] | 0 | 0 | |
Pension Plan [Member] | Domestic Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [1],[2] | 27 | 30 | |
Pension Plan [Member] | Domestic Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [1],[2] | 0 | 0 | |
Pension Plan [Member] | Foreign Equity Securities [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [1],[2] | 13 | 19 | |
Pension Plan [Member] | Foreign Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [1],[2] | 0 | 0 | |
Pension Plan [Member] | Foreign Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [1],[2] | 13 | 19 | |
Pension Plan [Member] | Foreign Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [1],[2] | 0 | 0 | |
Pension Plan [Member] | Derivative Financial Instruments, Assets [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [3] | 19 | 31 | |
Pension Plan [Member] | Derivative Financial Instruments, Assets [Member] | Fair Value, Inputs, Level 1 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [3] | 0 | 0 | |
Pension Plan [Member] | Derivative Financial Instruments, Assets [Member] | Fair Value, Inputs, Level 2 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [3] | 19 | 31 | |
Pension Plan [Member] | Derivative Financial Instruments, Assets [Member] | Fair Value, Inputs, Level 3 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [3] | 0 | 0 | |
Pension Plan [Member] | US Treasury Securities [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 12 | 22 | |
Pension Plan [Member] | US Treasury Securities [Member] | Fair Value, Inputs, Level 1 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 12 | 22 | |
Pension Plan [Member] | US Treasury Securities [Member] | Fair Value, Inputs, Level 2 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 0 | 0 | |
Pension Plan [Member] | US Treasury Securities [Member] | Fair Value, Inputs, Level 3 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 0 | 0 | |
Pension Plan [Member] | Municipal Bonds [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [4] | 5 | 5 | |
Pension Plan [Member] | Municipal Bonds [Member] | Fair Value, Inputs, Level 1 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [4] | 0 | 0 | |
Pension Plan [Member] | Municipal Bonds [Member] | Fair Value, Inputs, Level 2 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [4] | 5 | 5 | |
Pension Plan [Member] | Municipal Bonds [Member] | Fair Value, Inputs, Level 3 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [4] | 0 | 0 | |
Pension Plan [Member] | Domestic Corporate Debt Securities [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [4] | 86 | 82 | |
Pension Plan [Member] | Domestic Corporate Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [4] | 0 | 0 | |
Pension Plan [Member] | Domestic Corporate Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [4] | 86 | 82 | |
Pension Plan [Member] | Domestic Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [4] | 0 | 0 | |
Pension Plan [Member] | Foreign Corporate Debt Securities [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [2] | 21 | 19 | |
Pension Plan [Member] | Foreign Corporate Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [2] | 0 | 0 | |
Pension Plan [Member] | Foreign Corporate Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [2] | 21 | 19 | |
Pension Plan [Member] | Foreign Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [2] | 0 | 0 | |
Pension Plan [Member] | Assets, Total [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 188 | 218 | |
Pension Plan [Member] | Assets, Total [Member] | Fair Value, Inputs, Level 1 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 17 | 32 | |
Pension Plan [Member] | Assets, Total [Member] | Fair Value, Inputs, Level 2 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 171 | 186 | |
Pension Plan [Member] | Assets, Total [Member] | Fair Value, Inputs, Level 3 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 0 | 0 | |
Pension Plan [Member] | Derivative Financial Instruments, Liabilities [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [3] | (19) | (31) | |
Pension Plan [Member] | Derivative Financial Instruments, Liabilities [Member] | Fair Value, Inputs, Level 1 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [3] | 0 | 0 | |
Pension Plan [Member] | Derivative Financial Instruments, Liabilities [Member] | Fair Value, Inputs, Level 2 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [3] | (19) | (31) | |
Pension Plan [Member] | Derivative Financial Instruments, Liabilities [Member] | Fair Value, Inputs, Level 3 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [3] | 0 | 0 | |
Pension Plan [Member] | Liabilities, Total [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | (19) | (31) | |
Pension Plan [Member] | Liabilities, Total [Member] | Fair Value, Inputs, Level 1 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 0 | 0 | |
Pension Plan [Member] | Liabilities, Total [Member] | Fair Value, Inputs, Level 2 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | (19) | (31) | |
Pension Plan [Member] | Liabilities, Total [Member] | Fair Value, Inputs, Level 3 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 0 | 0 | |
Other Postretirement Benefit Plan [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 5 | 6 | |
Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 1 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | | 1 | |
Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 2 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | | 5 | |
Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 3 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | | 0 | |
Other Postretirement Benefit Plan [Member] | Cash and Cash Equivalents [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 1 | | |
Other Postretirement Benefit Plan [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 1 | | |
Other Postretirement Benefit Plan [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 0 | | |
Other Postretirement Benefit Plan [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 0 | | |
Other Postretirement Benefit Plan [Member] | Domestic Equity Securities [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [5],[6] | 1 | 1 | |
Other Postretirement Benefit Plan [Member] | Domestic Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [5],[6] | 0 | 0 | |
Other Postretirement Benefit Plan [Member] | Domestic Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [5],[6] | 1 | 1 | |
Other Postretirement Benefit Plan [Member] | Domestic Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [5],[6] | 0 | 0 | |
Other Postretirement Benefit Plan [Member] | Derivative Financial Instruments, Assets [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [7] | | 1 | |
Other Postretirement Benefit Plan [Member] | Derivative Financial Instruments, Assets [Member] | Fair Value, Inputs, Level 1 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [7] | | 0 | |
Other Postretirement Benefit Plan [Member] | Derivative Financial Instruments, Assets [Member] | Fair Value, Inputs, Level 2 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [7] | | 1 | |
Other Postretirement Benefit Plan [Member] | Derivative Financial Instruments, Assets [Member] | Fair Value, Inputs, Level 3 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [7] | | 0 | |
Other Postretirement Benefit Plan [Member] | US Treasury Securities [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | | 1 | |
Other Postretirement Benefit Plan [Member] | US Treasury Securities [Member] | Fair Value, Inputs, Level 1 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | | 1 | |
Other Postretirement Benefit Plan [Member] | US Treasury Securities [Member] | Fair Value, Inputs, Level 2 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | | 0 | |
Other Postretirement Benefit Plan [Member] | US Treasury Securities [Member] | Fair Value, Inputs, Level 3 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | | 0 | |
Other Postretirement Benefit Plan [Member] | Domestic Corporate Debt Securities [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [8] | 3 | 4 | |
Other Postretirement Benefit Plan [Member] | Domestic Corporate Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [8] | 0 | 0 | |
Other Postretirement Benefit Plan [Member] | Domestic Corporate Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [8] | 3 | 4 | |
Other Postretirement Benefit Plan [Member] | Domestic Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [8] | 0 | 0 | |
Other Postretirement Benefit Plan [Member] | Assets, Total [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 5 | 7 | |
Other Postretirement Benefit Plan [Member] | Assets, Total [Member] | Fair Value, Inputs, Level 1 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 1 | 1 | |
Other Postretirement Benefit Plan [Member] | Assets, Total [Member] | Fair Value, Inputs, Level 2 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 4 | 6 | |
Other Postretirement Benefit Plan [Member] | Assets, Total [Member] | Fair Value, Inputs, Level 3 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | $ 0 | 0 | |
Other Postretirement Benefit Plan [Member] | Derivative Financial Instruments, Liabilities [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [7] | | (1) | |
Other Postretirement Benefit Plan [Member] | Derivative Financial Instruments, Liabilities [Member] | Fair Value, Inputs, Level 1 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [7] | | 0 | |
Other Postretirement Benefit Plan [Member] | Derivative Financial Instruments, Liabilities [Member] | Fair Value, Inputs, Level 2 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [7] | | (1) | |
Other Postretirement Benefit Plan [Member] | Derivative Financial Instruments, Liabilities [Member] | Fair Value, Inputs, Level 3 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [7] | | 0 | |
Other Postretirement Benefit Plan [Member] | Liabilities, Total [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | | (1) | |
Other Postretirement Benefit Plan [Member] | Liabilities, Total [Member] | Fair Value, Inputs, Level 1 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | | 0 | |
Other Postretirement Benefit Plan [Member] | Liabilities, Total [Member] | Fair Value, Inputs, Level 2 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | | (1) | |
Other Postretirement Benefit Plan [Member] | Liabilities, Total [Member] | Fair Value, Inputs, Level 3 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | | $ 0 | |
| |
[1] | Equity securities are comprised of actively managed U.S. index funds and Europe, Australia, Far East ("EAFE") index funds. | |
[2] | The NAV is based on the fair value of the underlying assets owned by the equity index fund or fixed income investment vehicle per share multiplied by the number of units held as of the measurement date and are classified as Level 2 assets. | |
[3] | Derivative financial instruments consist of U.S Treasury futures. The fair value of these futures is determined by using quoted market prices of similar instruments. | |
[4] | U.S. Municipal and Corporate bonds are based on quoted bid prices for comparable securities in the marketplace. | |
[5] | Equity securities are comprised of actively managed U.S. index funds and EAFE index funds. | |
[6] | The NAV is based on the fair value of the underlying assets owned by the equity index fund or fixed income investment vehicle per share multiplied by the number of units held as of the measurement date and are classified as Level 2 assets. | |
[7] | Derivative financial instruments consist of U.S Treasury futures. The fair value of these futures is determined by using quoted market prices of similar instruments. | |
[8] | U.S. Corporate bonds are based on quoted bid prices for comparable securities in the marketplace. | |