Discontinued Operations - Components of Assets and Liabilities Held for Sale (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Assets
Assets held for sale	$ 1,910	$ 0
Discontinued Operations, Disposed of by Sale \| Prepaid Transaction
Assets
Accounts receivable	339
Inventory	142
Goodwill and intangible assets	1,425
Operating lease right-of-use assets	4
Assets held for sale	1,910
Liabilities
Accounts payable and accrued liabilities	422
Deferred revenue	180
Operating lease liabilities	4
Liabilities held for sale	606
Assets held for sale, net	$ 1,304

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