Equity Equity (Common Stock Dividends) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Dividends Payable [Line Items]
Dividends, Common Stock, Cash	$ 405	$ 416
Common Stock [Member]
Dividends Payable [Line Items]
Dividends Payable, Date Declared	Jan. 07, 2019	Jan. 05, 2018
Dividends Payable, Date of Record	Feb. 05, 2019	Feb. 05, 2018
Dividends Payable, Date to be Paid	Mar. 13, 2019	Mar. 13, 2018
Common Stock, Dividends, Per Share, Cash Paid	$ 0.42	$ 0.40
Dividends, Common Stock, Cash	$ 405	$ 416