Retirement Plans - Fair Value of Financial Assets of Funded Pension Plans (Detail) - USD ($) $ in Millions | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | $ 2,568 | $ 2,732 | |
Cash and Short-term Investment Funds | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | 50 | 101 | |
U.S. Equities (domestic) | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | 654 | 789 | |
International Equities (non-U.S.) | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | 409 | 434 | |
Global Equities (domestic and non-U.S.) | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | 205 | 240 | |
Treasury and Government Issued - Fixed Income | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | 240 | 271 | |
Government Related - Fixed Income | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | 37 | 35 | |
Mortgage-backed Securities - Fixed Income | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | 186 | 166 | |
Corporate - Fixed Income | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | 303 | 188 | |
Hedge Funds | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | 135 | 187 | |
Private Equity Funds | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | 170 | 140 | |
Real Estate Funds | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | 160 | 157 | |
Diversified Commodities Funds | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | 19 | 24 | |
Level 1 | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | 800 | 990 | |
Level 1 | Cash and Short-term Investment Funds | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | 3 | 32 | |
Level 1 | U.S. Equities (domestic) | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | 654 | 789 | |
Level 1 | International Equities (non-U.S.) | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | 92 | 104 | |
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 | 0 | 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 | 49 | 63 | |
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 | 1,006 | 991 | |
Level 2 | Cash and Short-term Investment Funds | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | 47 | 69 | |
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 | 29 | 34 | |
Level 2 | Global Equities (domestic and non-U.S.) | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | 203 | 238 | |
Level 2 | Treasury and Government Issued - Fixed Income | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | 240 | 271 | |
Level 2 | Government Related - Fixed Income | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | 37 | 34 | |
Level 2 | Mortgage-backed Securities - Fixed Income | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | 159 | 139 | |
Level 2 | Corporate - Fixed Income | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | 272 | 182 | |
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 | 19 | 24 | |
Level 3 | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | 61 | 4 | $ 10 |
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 | 0 | 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 | 0 | 0 | |
Level 3 | Private Equity Funds | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | 0 | 0 | |
Level 3 | Real Estate Funds | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | 61 | 2 | $ 8 |
Level 3 | Diversified Commodities Funds | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | 0 | 0 | |
Net Asset Value | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | 701 | 747 | |
Net Asset Value | Cash and Short-term Investment Funds | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | 0 | 0 | |
Net Asset Value | U.S. Equities (domestic) | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | 0 | 0 | |
Net Asset Value | International Equities (non-U.S.) | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | 288 | 296 | |
Net Asset Value | Global Equities (domestic and non-U.S.) | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | 0 | 0 | |
Net Asset Value | Treasury and Government Issued - Fixed Income | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | 0 | 0 | |
Net Asset Value | Government Related - Fixed Income | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | 0 | 0 | |
Net Asset Value | Mortgage-backed Securities - Fixed Income | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | 27 | 26 | |
Net Asset Value | Corporate - Fixed Income | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | 31 | 6 | |
Net Asset Value | Hedge Funds | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | 135 | 187 | |
Net Asset Value | Private Equity Funds | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | 170 | 140 | |
Net Asset Value | Real Estate Funds | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | 50 | 92 | |
Net Asset Value | Diversified Commodities Funds | | | |
Defined Benefit Plan Disclosure [Line Items] | | | |
Fair value of financial assets of funded pension plans | $ 0 | $ 0 | |