Leases - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Leases [Abstract]
Operating lease, right-of-use asset	$ 1,000
Total	1,105
Operating lease, liability, noncurrent	855
New ROU operating lease assets and liabilities entered into	$ 209
Weighted average remaining lease term	9 years
Weighted average discount rate	3.20%
Operating lease cost		$ 247	$ 169
Operating lease cost	$ 239
Cash payments	$ 223