Equity Equity (Common Stock Dividends) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Dividends Payable [Line Items]
Dividends, Common Stock, Cash	$ 419	$ 404	$ 419	$ 405
Common Stock [Member]
Dividends Payable [Line Items]
Dividends Payable, Date Declared	Apr. 28, 2020	Jan. 07, 2020	Apr. 23, 2019	Jan. 07, 2019
Dividends Payable, Date of Record	May 08, 2020	Feb. 04, 2020	May 07, 2019	Feb. 05, 2019
Dividends Payable, Date to be Paid	Jun. 12, 2020	Mar. 13, 2020	Jun. 13, 2019	Mar. 13, 2019
Common Stock, Dividends, Per Share, Cash Paid	$ 0.460	$ 0.440	$ 0.440	$ 0.420	$ 0.900	$ 0.860
Dividends, Common Stock, Cash	$ 419	$ 404	$ 419	$ 405	$ 823	$ 824