Retirement Plans - Fair Value of Financial Assets of Funded Pension Plans (Detail) - USD ($) $ in Millions | Dec. 31, 2015 | Dec. 31, 2014 |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | $ 2,206 | $ 2,251 |
Cash and Short-term Investment Funds | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 34 | 53 |
U.S. Equities (domestic) | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 556 | 719 |
International Equities (non-U.S.) | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 425 | 249 |
Global Equities (domestic and non-U.S.) | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 219 | 228 |
Treasury and Government Issued - Fixed Income | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 213 | 222 |
Government Related - Fixed Income | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 7 | 8 |
Mortgage-backed Securities - Fixed Income | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 176 | 148 |
Corporate - Fixed Income | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 157 | 140 |
Hedge Funds | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 216 | 302 |
Private Equity Funds | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 122 | 105 |
Real Estate Funds | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 64 | 60 |
Diversified Commodities Funds | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 17 | 17 |
Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 729 | 822 |
Level 1 | Cash and Short-term Investment Funds | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 0 | 6 |
Level 1 | U.S. Equities (domestic) | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 556 | 719 |
Level 1 | International Equities (non-U.S.) | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 159 | 72 |
Level 1 | Global Equities (domestic and non-U.S.) | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 2 | 10 |
Level 1 | Treasury and Government Issued - Fixed Income | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 0 | 0 |
Level 1 | Government Related - Fixed Income | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 0 | 0 |
Level 1 | Mortgage-backed Securities - Fixed Income | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 0 | 0 |
Level 1 | Corporate - Fixed Income | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 0 | 3 |
Level 1 | Hedge Funds | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 0 | 0 |
Level 1 | Private Equity Funds | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 0 | 0 |
Level 1 | Real Estate Funds | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 12 | 12 |
Level 1 | Diversified Commodities Funds | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 0 | 0 |
Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 1,084 | 972 |
Level 2 | Cash and Short-term Investment Funds | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 34 | 47 |
Level 2 | U.S. Equities (domestic) | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 0 | 0 |
Level 2 | International Equities (non-U.S.) | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 266 | 177 |
Level 2 | Global Equities (domestic and non-U.S.) | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 217 | 218 |
Level 2 | Treasury and Government Issued - Fixed Income | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 213 | 222 |
Level 2 | Government Related - Fixed Income | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 6 | 7 |
Level 2 | Mortgage-backed Securities - Fixed Income | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 174 | 147 |
Level 2 | Corporate - Fixed Income | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 157 | 137 |
Level 2 | Hedge Funds | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 0 | 0 |
Level 2 | Private Equity Funds | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 0 | 0 |
Level 2 | Real Estate Funds | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 0 | 0 |
Level 2 | Diversified Commodities Funds | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 17 | 17 |
Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 393 | 457 |
Level 3 | Cash and Short-term Investment Funds | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 0 | 0 |
Level 3 | U.S. Equities (domestic) | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 0 | 0 |
Level 3 | International Equities (non-U.S.) | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 0 | 0 |
Level 3 | Global Equities (domestic and non-U.S.) | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 0 | 0 |
Level 3 | Treasury and Government Issued - Fixed Income | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 0 | 0 |
Level 3 | Government Related - Fixed Income | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 1 | 1 |
Level 3 | Mortgage-backed Securities - Fixed Income | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 2 | 1 |
Level 3 | Corporate - Fixed Income | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 0 | 0 |
Level 3 | Hedge Funds | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 216 | 302 |
Level 3 | Private Equity Funds | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 122 | 105 |
Level 3 | Real Estate Funds | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 52 | 48 |
Level 3 | Diversified Commodities Funds | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | $ 0 | $ 0 |