Derivative Instruments and Hedging Activities Derivative Instruments and Hedging Activities - Hedged Items in Fair Value Hedging Relationship (Details) $ in Millions	Dec. 31, 2018 USD ($)
Hedged Items In Fair Value Hedging Relationship [Line Items]
Amortized cost of closed prepayment assets	$ 8,300
Amortized Cost Of Closed Prepayable Assets Designated In Fair Value Hedges	4,000
Hedged LOLA assets Cumulative Basis Adjustment	26
Available-for-sale Securities
Hedged Items In Fair Value Hedging Relationship [Line Items]
Carrying Amount of Assets	14,067
Hedged Asset, Fair Value Hedge, Cumulative Increase (Decrease)	(6)
Hedged Asset, Discontinued Fair Value Hedge, Cumulative Increase (Decrease)	(2)
Interest-bearing deposits
Hedged Items In Fair Value Hedging Relationship [Line Items]
Carrying Amount Of Liabilities	(13,101)
Hedged Liability, Fair Value Hedge, Cumulative Increase (Decrease)	247
Hedged Liability, Discontinued Fair Value Hedge, Cumulative Increase (Decrease)	0
Securitized debt obligations
Hedged Items In Fair Value Hedging Relationship [Line Items]
Carrying Amount Of Liabilities	(5,887)
Hedged Liability, Fair Value Hedge, Cumulative Increase (Decrease)	168
Hedged Liability, Discontinued Fair Value Hedge, Cumulative Increase (Decrease)	143
Senior and subordinated notes
Hedged Items In Fair Value Hedging Relationship [Line Items]
Carrying Amount Of Liabilities	(23,572)
Hedged Liability, Fair Value Hedge, Cumulative Increase (Decrease)	315
Hedged Liability, Discontinued Fair Value Hedge, Cumulative Increase (Decrease)	$ 392

Amortized cost of closed prepayable assets designated in fair value hedges

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- Definition

Amortized cost of closed prepayment assets for LOLA hedging purpose

+ References

No definition available.

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- Definition

Carry amount of assets hedged in fair value hedging relationship

+ References

No definition available.

+ Details

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- Definition

The carry amount of liabilities in fair value hedging relationship

+ References

No definition available.

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- Definition

[Line Items] for Table shows the carrying amount and associated cumulative basis adjustment related to the application of hedge accounting that is included in the carrying amount of hedged assets and liabilities in fair value hedging relationships.

+ References

No definition available.

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- Definition

Hedged Assets Fair Value Hedge Cumulative Increase Decrease - LOLA

+ References

No definition available.

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- Definition

Amount of cumulative increase (decrease) in fair value of hedged asset in fair value hedge, attributable to hedged risk, remaining after discontinued hedge.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4EE
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL109999712-113959

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- Definition

Amount of cumulative increase (decrease) in fair value of hedged asset in fair value hedge, attributable to hedged risk.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4EE
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL109999712-113959

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- Definition

Amount of cumulative increase (decrease) in fair value of hedged liability in fair value hedge, attributable to hedged risk, remaining after discontinued hedge.

+ References

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- Definition

Amount of cumulative increase (decrease) in fair value of hedged liability in fair value hedge, attributable to hedged risk.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4EE
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL109999712-113959

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