Income Taxes (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2017
Income Tax Contingency [Line Items]
Deferred Tax Liabilities, Net	$ 2,702	$ 2,019
Income tax expense	$ 1,830	$ 1,666	$ 1,178
Income tax expense (benefit) per diluted share	$ 7.41	$ 6.55	$ 4.53
Effective Income Tax Reconciliation Patient Protection Affordable Care Act Health Insurance Provider Fee	$ 0	$ 330	$ 0
Unrecognized tax benefits that would impact effective tax rate in future periods, if recognized	250	227
Unrecognized tax benefits that would impact additional paid-in capital in future periods, if recognized	2
Protective state income tax refund claims filed				$ 310
Net interest expense (benefit)	9	7	(11)
Interest accrued	42	33
Unrecognized tax benefit change reasonably possible due to tax settlements - lower amount	(14)
Unrecognized tax benefit change reasonably possible due to tax settlements - upper amount	(105)
Income Taxes Receivable	173	262
Income Taxes Paid	$ 1,299	$ 1,790	$ 1,403
Health Insurance Provider fee [Member]
Income Tax Contingency [Line Items]
Income tax expense (benefit) per diluted share		$ 1.30
Effective Income Tax Reconciliation Patient Protection Affordable Care Act Health Insurance Provider Fee		$ 330
Latest Tax Year [Member] | Federal [Member]
Income Tax Contingency [Line Items]
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2041
Latest Tax Year [Member] | State [Member]
Income Tax Contingency [Line Items]
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2041
Earliest Tax Year [Member] | Federal [Member]
Income Tax Contingency [Line Items]
Operating Loss Carryforwards, Expiration Date	Jan. 01, 2032
Earliest Tax Year [Member] | State [Member]
Income Tax Contingency [Line Items]
Operating Loss Carryforwards, Expiration Date	Jan. 01, 2022
Indefinite Carryforward Period | Federal [Member]
Income Tax Contingency [Line Items]
Net operating loss carry forwards	$ 153
Limited Carryforward Period | Federal [Member]
Income Tax Contingency [Line Items]
Net operating loss carry forwards	181
Other Noncurrent Assets [Member]
Income Tax Contingency [Line Items]
Deferred Tax Assets, Net	103	0
Deferred tax liabilities, net [Member]
Income Tax Contingency [Line Items]
Deferred Tax Liabilities, Net	$ 2,805	$ 2,019