Short-term and Long-term Debt - Short-term and Long-term Debt (Parenthetical) (Detail)	6 Months Ended	12 Months Ended
	Jul. 01, 2017	Dec. 31, 2016	Feb. 15, 2017
5.50% Unsecured Notes Due 2017 [Member]
Schedule Of Debt Instruments [Line Items]
Unsecured notes, interest rate	5.50%	5.50%
Unsecured notes, maturity year	2017	2017
4.25% Unsecured Notes Due 2018 [Member]
Schedule Of Debt Instruments [Line Items]
Unsecured notes, interest rate	4.25%	4.25%
Unsecured notes, maturity year	2018	2018
6.70% Unsecured Notes Due 2019 [Member]
Schedule Of Debt Instruments [Line Items]
Unsecured notes, interest rate	6.70%	6.70%
Unsecured notes, maturity year	2019	2019
6.125% Unsecured Notes Due 2021 [Member]
Schedule Of Debt Instruments [Line Items]
Unsecured notes, interest rate	6.125%	6.125%
Unsecured notes, maturity year	2021	2021
3.25% Unsecured Notes Due 2027 [Member]
Schedule Of Debt Instruments [Line Items]
Unsecured notes, interest rate	3.25%	3.25%	3.25%
Unsecured notes, maturity year	2027	2027