Equity Equity (Dividends) (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended								12 Months Ended			126 Months Ended
	Feb. 12, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2020
Subsequent Event [Line Items]
Common Stock, Dividends, Per Share, Cash Paid		$ 0.1433	$ 0.1433	$ 0.1433	$ 0.1433
Dividends declared on common stock (per share amount)		$ 0.29	$ 0.14	$ 0	$ 0.14	$ 0.28	$ 0.14	$ 0	$ 0.14	$ 0.5804	$ 0.5528	$ 0.53
Treasury Stock, Value, Acquired, Cost Method													$ 1,900
Acquisition of treasury stock (shares)													154,300,000
Treasury Stock Acquired, Average Cost Per Share													$ 12.12
Stock Repurchase Program, Remaining Authorized Repurchase Amount		$ 264								$ 264			$ 264
Treasury stock, shares (in shares)		153,028,526				153,891,260				153,028,526	153,891,260		153,028,526
Subsequent Event
Subsequent Event [Line Items]
Dividends declared on common stock (per share amount)	$ 0.1505