Restructuring - Schedule of Accrued Restructuring Included in Accrued Expenses and Other Liabilities by Cost Type (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Restructuring Reserve [Roll Forward]
Balance, beginning	$ 0
Costs charged to expense	132	$ 10	$ 15
Cash payments	(56)
Non-cash charge adjustment	(41)
Balance, ending	35	0
Severance and employee related costs
Restructuring Reserve [Roll Forward]
Balance, beginning	0
Costs charged to expense	76
Cash payments	(44)
Non-cash charge adjustment	0
Balance, ending	32	0
Facilities and related costs
Restructuring Reserve [Roll Forward]
Balance, beginning	0
Costs charged to expense	29
Cash payments	0
Non-cash charge adjustment	(29)
Balance, ending	0	0
Other costs
Restructuring Reserve [Roll Forward]
Balance, beginning	0
Costs charged to expense	27
Cash payments	(12)
Non-cash charge adjustment	(12)
Balance, ending	$ 3	$ 0