Restructuring and Other Charges (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2020	Dec. 31, 2019
Restructuring Cost and Reserve [Line Items]
Integration activities charges	$ 92	$ 140
Non-cash impairment charge associated with early termination	40	40
Accelerated amortization expense included within finance lease expense	7	45
Accelerated amortization expense	24	34
Employee Severance
Restructuring Cost and Reserve [Line Items]
Severance and other separation costs	37	77
Employee severance and other separation costs accrual	29	29	$ 14
Share-based compensation costs	$ 15	$ 23