Earnings per Share (Weighted Average Shares Outstanding) (Details) - shares shares in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Weighted Average Number of Shares Outstanding, Basic and Diluted	998	990	996	989

Average number of shares or units issued and outstanding that are used in calculating basic and diluted earnings per share (EPS).

No definition available.

Name:	us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration