Other Current Assets (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Other Assets [Abstract]
Derivative Asset	$ 634		$ 449
Deferred receivables consideration	399		307
Receivables from Customers	496		477
Financing Receivable, Net	487		413
Premiums Receivable, Net	132		129
Prepaid Expense, Current	259		232
Tax receivables	585		425
Other Receivables	430		371
Other current assets	312		372
Total other current assets	3,734		3,175
Financing Receivable, Allowance for Credit Losses	7		6
Interest on financing receivables	7	$ 7
Reinsurance Recoverables	$ 114		$ 91