Leases Lease Balance Sheet (Details 2) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Assets and Liabilities, Lessee [Abstract]
Operating lease right-of-use assets	$ 1,533	$ 1,511
Operating Lease, Liability, Current	263	261
Operating Lease, Liability, Noncurrent	1,343	1,308
Total operating lease liabilities	$ 1,606	$ 1,569