Derivatives and Hedging Activities (Details Textuals) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Derivatives and Hedging Activities (Textuals) [Abstract]
Net reduction in interest expense on long term debt and other	$ 24	$ 55	$ 105	$ 173
Margin On Interest Rate Swap Not Netted	152		152		$ 169
Derivative [Line Items]
Notional amount of long-term debt	20,700		20,700		17,700
Effective portion of gain (loss) on hedges	(184)	(18)	(515)	25
Net hedge ineffectiveness	0	0
Other Expense [Member]
Derivative [Line Items]
Gain (Loss) in Changes of Fair Value of Derivatives not designated as hedges	(15)	(4)	(36)	(12)
Gain on embedded derivatives	1	1	(1)	7
Net Investment Hedging [Member] | Other Expense [Member]
Derivative [Line Items]
Amount reclassified from AOCI into income	(18)	0	(18)	5
Net hedge ineffectiveness	0	$ 0	0	$ 0
Net Investment Hedging [Member] | Net Investment Hedging [Member] | Other Expense [Member]
Derivative [Line Items]
Amount reclassified from AOCI into income	0
Not Sold Or Repledged [Member]
Derivative [Line Items]
Securities received as collateral	0		0		18
Risk Exposure Low [Member]
Derivative [Line Items]
Total derivative assets					$ 537
Interest Rate Contract [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Derivative [Line Items]
Total derivative assets	11		11
Derivative Liability	87		87
Derivative Assets, Cleared Collateral, Offset	11		11
Derivative Liabilities, Cleared Collateral, Offset	$ 79		$ 79