Derivatives and Hedging Activities (Details Textuals) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Derivative [Line Items]
Derivative asset not offset	$ 0		$ 0		$ 0
Derivative liabilities not offset	0		0		0
Margin on interest rate swaps	87,000,000		87,000,000		84,000,000
Cumulative amount of fair value hedging adjustment	322,000,000		322,000,000		(241,000,000)
Net increase (reduction) in interest expense on long term debt and other	28,000,000	$ 20,000,000	102,000,000	$ 19,000,000
Other Expense [Member]
Derivative [Line Items]
Gain (loss) in changes in fair value of derivatives not designated as hedges	25,000,000	(8,000,000)	52,000,000	26,000,000
Changes in fair value of an embedded derivative		5,000,000		11,000,000
Fair Value Hedging [Member]
Derivative [Line Items]
Notional amount of long-term debt	22,600,000,000		22,600,000,000		24,000,000,000.0
Net Investment Hedges [Member]
Derivative [Line Items]
Notional amounts of derivatives	10,000,000,000.0		10,000,000,000.0		9,600,000,000
Reported Value Measurement [Member]
Derivative [Line Items]
Notional amount of long-term debt	22,800,000,000		22,800,000,000		$ 23,700,000,000
Accumulated Other Comprehensive Loss [Member]
Derivative [Line Items]
Gain (loss) on net investment hedges, net of taxes	$ 138,000,000	$ (22,000,000)	$ 63,000,000	$ 136,000,000