Equity (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended					9 Months Ended
		Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Dividends Payable [Line Items]
Conversion factor, 6.785% Mandatory Convertible Preferred Stock							8.8043
Preferred Stock, Dividends, Per Share, Cash Paid				$ 17.1875	$ 17.1875	$ 17.1875
Common Stock, Dividends, Per Share, Cash Paid	[1]	$ 1.20	$ 1.20	$ 1.20
Dividends, Common Stock, Cash	[1]	$ 521		$ 504		$ 504
Dividends, Preferred Stock, Cash				$ 28	$ 28	$ 28
Common stock repurchased during period, shares		500,000
Purchases of Common Stock							$ (75)	$ (44)
Availability Under ATM		$ 750					$ 750
6.875% Mandatory Convertible Preferred Stock [Member]
Dividends Payable [Line Items]
Conversion of preferred stock to common stock		2,000,000					2,000,000
Common Stock [Member]
Dividends Payable [Line Items]
Conversion of Stock, Shares Issued							14,000,000
Dividends Payable, Date Declared	[1]	Aug. 06, 2020		Feb. 20, 2020		May 14, 2020
Dividends Payable, Date of Record	[1]	Sep. 15, 2020		Mar. 13, 2020		Jun. 12, 2020
Dividends Payable, Date to be Paid	[1]	Sep. 30, 2020		Mar. 31, 2020		Jun. 30, 2020
Preferred Stock [Member]
Dividends Payable [Line Items]
Dividends Payable, Date Declared				Mar. 12, 2020	Dec. 09, 2019	Jun. 19, 2020
Dividends Payable, Date of Record				Apr. 15, 2020	Jan. 15, 2020	Jul. 15, 2020
Dividends Payable, Date to be Paid				May 01, 2020	Feb. 03, 2020	Aug. 03, 2020

[1] Inclusive of dividends accrued for holders of unvested restricted stock units, which will be paid when and if the restricted stock units vest.