Annual report pursuant to Section 13 and 15(d)

Income Taxes - Reconciliation of the Change in Unrecognized Tax Benefits (Details)

v3.10.0.1
Income Taxes - Reconciliation of the Change in Unrecognized Tax Benefits (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]      
Balance, January 1 $ 1,773 $ 875 $ 1,095
Increases related to positions taken during the current year 395 292 104
Increases related to positions taken during prior years 406 750 1,318
Decreases related to positions taken during prior years (371) (122) (1,091)
Settlements (6) (17) (503)
Expiration of statute of limitations 0 (5) (48)
Balance, December 31 $ 2,197 $ 1,773 $ 875