Other Current Assets (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Jan. 01, 2018	Dec. 31, 2017
Other Assets [Abstract]
Derivative Asset	$ 950		$ 950			$ 449
Deferred receivables consideration	475		475			307
Receivables from Customers	455		455			477
Financing Receivable, Net	579		579			413
Premiums Receivable, Net	48		48			129
Prepaid Expense, Current	257		257			232
Tax receivables	416		416			425
Other Receivables	324		324			371
Other current assets	203		203			372
Total other current assets	3,707		3,707		$ 3,175	3,175
Financing Receivable, Allowance for Credit Losses	3		3			6
Interest on financing receivables	6	$ 6	18	$ 18
Asset Impairment Charges		$ 62	21	$ 80
Reinsurance Recoverables	$ 67		$ 67			$ 91