Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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- Definition

Average fixed interest rate related to the group of interest rate derivatives.

+ References

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- Definition

Average remaining period until maturity of the derivative contract, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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- Definition

Average variable interest rate related to the group of interest rate derivatives.

+ References

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Derivative Instruments and Hedging Activities Schedule of Interest Rate Swap Payers (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017	Jun. 30, 2018	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Derivative [Line Items]
Notional	$ 41,330,283,000	$ 31,226,878,000	$ 28,618,861,000	$ 24,113,321,000	$ 16,988,116,000	$ 18,802,500,000
Interest Rate Swap [Member] \| Long [Member]
Derivative [Line Items]
Notional	$ 23,401,328,000	$ 22,920,135,000
Weighted Average Fixed Interest Rate	1.876%	1.694%
Weighted Average Variable Interest Rate	2.343%	1.493%
Weighted Average Remaining Maturity	3 years 9 months 7 days	3 years 3 days
Interest Rate Swap [Member] \| Derivative Maturity Within One Year From Balance Sheet Date [Member] \| Long [Member]
Derivative [Line Items]
Notional	$ 1,000,000,000	$ 4,320,000,000
Weighted Average Fixed Interest Rate	1.008%	1.155%
Weighted Average Variable Interest Rate	2.336%	1.508%
Weighted Average Remaining Maturity	0 days	15 days
Interest Rate Swap [Member] \| Derivative Maturity Over One And Within Two Years From Balance Sheet Date [Member] \| Long [Member]
Derivative [Line Items]
Notional	$ 4,336,897,000	$ 5,448,135,000
Weighted Average Fixed Interest Rate	1.769%	1.767%
Weighted Average Variable Interest Rate	2.336%	1.386%
Weighted Average Remaining Maturity	1 year 14 days	1 year 9 months 14 days
Interest Rate Swap [Member] \| Derivative Maturity Over Two And Within Three Years From Balance Sheet Date [Member] \| Long [Member]
Derivative [Line Items]
Notional	$ 5,140,000,000	$ 5,490,000,000
Weighted Average Fixed Interest Rate	1.705%	1.945%
Weighted Average Variable Interest Rate	2.334%	1.509%
Weighted Average Remaining Maturity	2 years 25 days	2 years 10 months 13 days
Interest Rate Swap [Member] \| Derivative Maturity Over Three And Within Four Years From Balance Sheet Date [Member] \| Long [Member]
Derivative [Line Items]
Notional	$ 4,117,000,000	$ 2,417,000,000
Weighted Average Fixed Interest Rate	1.55%	1.788%
Weighted Average Variable Interest Rate	2.362%	1.628%
Weighted Average Remaining Maturity	2 years 11 months 8 days	3 years 11 months 1 day
Interest Rate Swap [Member] \| Derivative Maturity Over Four Years From Balance Sheet Date [Member] \| Long [Member]
Derivative [Line Items]
Notional	$ 8,807,431,000	$ 5,245,000,000
Weighted Average Fixed Interest Rate	2.309%	1.764%
Weighted Average Variable Interest Rate	2.343%	1.516%
Weighted Average Remaining Maturity	7 years 1 month 20 days	6 years 5 months 8 days
Forward Starting Interest Rate Swap [Member]
Derivative [Line Items]
Notional	$ 567,800,000	$ 570,000,000.0
Weighted Average Fixed Interest Rate	2.80%	2.10%