Leases - ROU Assets and Liabilities (Details) $ in Millions	Dec. 31, 2019 USD ($)
Assets [Abstract]
ROU assets (recorded within other long-term assets)	$ 661
Liabilities [Abstract]
Short-term (recorded within accounts payable and accrued expenses)	161
Long-term (recorded within other long-term liabilities)	622
Total operating lease liabilities	$ 783