Fair Value Disclosures - Narrative (Details) - Level 3 [Member] - USD ($) $ in Billions	Mar. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset and liability fair value	$ 6.5	$ 6.0
Percent of level three fair value assets and liabilities	33.00%	32.00%
Financial instruments level three percent	72.00%	73.00%

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.

No definition available.

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