Income Tax - Additional Information (Detail) - USD ($) $ in Millions		3 Months Ended		12 Months Ended
	Jan. 01, 2018	Dec. 31, 2017	Dec. 31, 2016	Sep. 30, 2018
Income Taxes [Line Items]
Net discrete tax (benefits) charges related to tax settlements		$ 188
Impact of the Tax Cuts and Jobs Act of 2017		$ 185
Income tax rate		35.00%
Provisional tax expense		$ 13
Income tax rate for aggregate cash position		15.50%
Income tax rate for exceeds aggregate cash position		8.00%
Provisional charge		$ 149
Percentage of deduction for dividends from specified foreign corporations		100.00%
Provisional amount to tax expense		$ 23
Percentage of tax on foreign income in excess of a deemed return on tangible assets of foreign corporations	10.50%
Uncertain tax positions from expirations of statute of limitations		$ 1	$ 2
Earliest Tax Year [Member] | United States Internal Revenue Service (IRS) [Member]
Income Taxes [Line Items]
Tax years remain subject to examination		2013
Latest Tax Year [Member] | United States Internal Revenue Service (IRS) [Member]
Income Taxes [Line Items]
Tax years remain subject to examination		2015
State Tax Authorities [Member] | Earliest Tax Year [Member]
Income Taxes [Line Items]
Tax years remain subject to examination		2005
State Tax Authorities [Member] | Latest Tax Year [Member]
Income Taxes [Line Items]
Tax years remain subject to examination		2015
Non-U.S. Jurisdictions [Member] | Earliest Tax Year [Member]
Income Taxes [Line Items]
Tax years remain subject to examination		2002
Non-U.S. Jurisdictions [Member] | Latest Tax Year [Member]
Income Taxes [Line Items]
Tax years remain subject to examination		2016
Scenario Forecast [Member]
Income Taxes [Line Items]
Income tax rate				24.53%
Subsequent Event [Member]
Income Taxes [Line Items]
Income tax rate	21.00%
Maximum [Member]
Income Taxes [Line Items]
Net discrete tax (benefits) charges related to tax settlements			$ (1)