Stockholders' Equity and Accumulated Other Comprehensive Loss - Additional Information (Details) - USD ($) $ in Millions		9 Months Ended
	Apr. 01, 2018	Sep. 30, 2018	Sep. 30, 2017
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, authorized amount		$ 2,000
Repurchases of common stock, shares		21,300,000
Stock repurchase program, remaining authorized repurchase amount		$ 719
Repurchases of common stock, purchase price		1,561	$ 625
Treasury Stock [member]
Equity, Class of Treasury Stock [Line Items]
Repurchases of common stock, purchase price		$ 1,561	$ 625
The Blackstone Group And Affiliates [Member]
Equity, Class of Treasury Stock [Line Items]
Repurchases of common stock, shares		1,250,000
Other stockholder [member]
Equity, Class of Treasury Stock [Line Items]
Repurchases of common stock, shares	16,500,000.0	16,500,000
Repurchases of common stock, purchase price	$ 1,171