Shareholders' Equity - Additional Information (Details) - USD ($)	May 01, 2018	Mar. 31, 2018
$210 billion share repurchase program in effect as of March 31, 2018
Stock Repurchase Program [Line Items]
Maximum amount authorized for repurchase of common stock		$ 210,000,000,000
Share repurchase program, amount utilized		$ 199,600,000,000
$100 billion share repurchase program announced on May 1, 2018 | Subsequent event
Stock Repurchase Program [Line Items]
Maximum amount authorized for repurchase of common stock	$ 100,000,000,000