Retirement Plans - Fair Value of Financial Assets of Funded Pension Plans (Detail) - USD ($) $ in Millions | Dec. 31, 2016 | Dec. 31, 2015 |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | $ 2,284 | $ 2,206 |
Cash and Short-term Investment Funds | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 88 | 34 |
U.S. Equities (domestic) | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 550 | 556 |
International Equities (non-U.S.) | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 435 | 425 |
Global Equities (domestic and non-U.S.) | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 199 | 219 |
Treasury and Government Issued - Fixed Income | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 202 | 213 |
Government Related - Fixed Income | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 38 | 7 |
Mortgage-backed Securities - Fixed Income | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 166 | 176 |
Corporate - Fixed Income | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 187 | 157 |
Hedge Funds | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 209 | 216 |
Private Equity Funds | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 126 | 122 |
Real Estate Funds | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 62 | 64 |
Diversified Commodities Funds | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 22 | 17 |
Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 732 | 729 |
Level 1 | Cash and Short-term Investment Funds | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 9 | 0 |
Level 1 | U.S. Equities (domestic) | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 550 | 556 |
Level 1 | International Equities (non-U.S.) | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 160 | 159 |
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 | 2 |
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 | 1 | 0 |
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 | 10 | 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 | 1,163 | 1,084 |
Level 2 | Cash and Short-term Investment Funds | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 79 | 34 |
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 | 275 | 266 |
Level 2 | Global Equities (domestic and non-U.S.) | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 197 | 217 |
Level 2 | Treasury and Government Issued - Fixed Income | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 202 | 213 |
Level 2 | Government Related - Fixed Income | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 38 | 6 |
Level 2 | Mortgage-backed Securities - Fixed Income | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 164 | 174 |
Level 2 | Corporate - Fixed Income | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 186 | 157 |
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 | 22 | 17 |
Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 389 | 393 |
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 | 0 | 1 |
Level 3 | Mortgage-backed Securities - Fixed Income | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 2 | 2 |
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 | 209 | 216 |
Level 3 | Private Equity Funds | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 126 | 122 |
Level 3 | Real Estate Funds | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | 52 | 52 |
Level 3 | Diversified Commodities Funds | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of financial assets of funded pension plans | $ 0 | $ 0 |