Derivative Financial Instruments Derivative Financial Instruments (Schedule of Net Investment Hedges) (Details) - EUR (€) € in Millions	Jun. 30, 2021	Dec. 31, 2020
Foreign Currency Denominated Debt [Member] \| Net Investment Hedging [Member]
Derivative [Line Items]
Notional Amount of Nonderivative Instruments	€ 1,358	€ 1,358

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.

Name:	us-gaap_DerivativeLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration