Leases - Assets and Liabilities (Details) $ in Millions	Dec. 31, 2019 USD ($)
Assets [Abstract]
Operating lease assets	$ 554
Finance lease assets	41
Total lease assets	595
Current liabilities:
Operating lease liabilities	122
Finance lease liabilities	13
Total lease liabilities, current	135
Non-current liabilities:
Operating lease liabilities	497
Finance lease liabilities	16
Total lease liabilities, non-current	$ 513