Derivatives and Hedging Activities (Details Textuals) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivatives and Hedging Activities (Textuals) [Abstract]
Net reduction in interest expense on long term debt and other	$ (51)	$ 133	$ 224
Margin on interest rate swap not netted	84	146
Derivative [Line Items]
Total derivatives assets, net	396	124
Other Expense [Member]
Derivative [Line Items]
Gain (Loss) in changes of Fair Value of Derivatives not designated as hedges	60	(29)	1
Gain on embedded derivatives	(11)	0	9
Fair Value Hedges [Member]
Derivative [Line Items]
Notional amount of long-term debt	24,000	23,800
Cumulative amount of fair value hedging adjustments	241	182
Net Investment Hedges [Member]
Derivative [Line Items]
Effective portion of gain (loss) on hedges	328	(370)	281
Notional Amount of Foreign Currency Derivatives	9,600	9,500
Net Investment Hedges [Member] | Other Expense [Member]
Derivative [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	1	(31)	$ (5)
Credit Valuation Adjustment [Member]
Derivative [Line Items]
Notional amount of long-term debt	0	0
Not Sold Or Repledged [Member]
Derivative [Line Items]
Securities received as collateral	0	0
Risk Exposure Low [Member]
Derivative [Line Items]
Total derivatives assets, net	0	0
Significant Counterparties [Member]
Derivative [Line Items]
Total derivatives assets, net	0	0
Total derivatives liabilities, net	0
Carrying Value [Member]
Derivative [Line Items]
Notional amount of long-term debt	$ 23,700	$ 23,600