v3.10.0.1
Equity - Summary of Common Stock Purchases (Details) - USD ($)
shares in Millions, $ in Millions
 2 Months Ended 12 Months Ended
Jun. 20, 2016
Mar. 10, 2016
Mar. 11, 2018
 [1]
Dec. 31, 2018
 [1]
Dec. 31, 2017
 [2]
Dec. 31, 2016
 [3]
Equity [Abstract]            
Shares of common stock purchased 18 136   307 150 154
Cost of purchase     $ 8,200 $ 12,198 [4] $ 5,000 [4] $ 5,000 [4]
[1] Represents shares purchased pursuant to the accelerated share repurchase agreement with Citibank entered into on March 12, 2018, as well as other share repurchases. See above for additional information.
[2] Represents shares purchased pursuant to the accelerated share repurchase agreement with Citibank entered into on February 2, 2017. See above for additional information.
[3] Represents shares purchased pursuant to the accelerated share repurchase agreement entered into on March 8, 2016. See above for additional information.
[4] Amounts may not add due to rounding.