Borrowings and Other Financing Instruments Forward Equity Agreement (Details) - Forward Equity Agreements [Member] - USD ($) shares in Millions, $ in Millions	Sep. 29, 2019	Nov. 30, 2018
Forward Contract Indexed to Issuer's Equity [Line Items]
Common Stock, Value, to be Issued through Forward Equity Agreement		$ 459
Common Stock, Shares to be Issued through forward Equity Agreement		9.4
Common stock, initial shares in an agreement		8.1
Common stock, additional shares in an agreement		1.2
Common Stock, Shares Issued through Forward Equity Agreement	9.4
Common Stock, Value Issued through Forward Equity Agreement	$ 453