Condensed Financial Information (Parent Company) (Long-term Debt - Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Jun. 30, 2020
Condensed Financial Statements, Captions [Line Items]
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net	$ 82	$ 90
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	109
Long-term Debt, Maturities, Repayments of Principal in Year Two	1,000
Long-term Debt, Maturities, Repayments of Principal in Year Three	1,800
Long-term Debt, Maturities, Repayments of Principal in Year Four	1,200
Long-term Debt, Maturities, Repayments of Principal in Year Five	566
Long-term Debt, Maturities, Repayments of Principal after Year Five	9,200
Debt Instrument, Face Amount		3,200
Parent Company
Condensed Financial Statements, Captions [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	0
Long-term Debt, Maturities, Repayments of Principal in Year Two	1,300
Long-term Debt, Maturities, Repayments of Principal in Year Three	1,500
Long-term Debt, Maturities, Repayments of Principal in Year Four	1,200
Long-term Debt, Maturities, Repayments of Principal in Year Five	582
Long-term Debt, Maturities, Repayments of Principal after Year Five	10,100
Senior Notes	12,814	13,463
Parent Company | Senior Notes Unaffiliated [Member]
Condensed Financial Statements, Captions [Line Items]
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net	77	85
Senior Notes	$ 12,814	$ 13,463
Parent Company | Senior Notes, Affiliated [Member]
Condensed Financial Statements, Captions [Line Items]
Senior Notes			$ 250