Slicers (applies to each fact value in each table cell)

Reporting Entity [Axis]

0001156039 (http://www.sec.gov/CIK)

Income Tax Disclosure [Abstract]	Period [Axis]
	2016-01-01 - 2016-12-31
Income Tax Disclosure [Abstract]
Components Of Deferred Income Taxes	The components of deferred income taxes at December 31 are as follows:   2016   2015 Deferred tax assets relating to:       Retirement benefits $ 362.9   $ 364.8 Accrued expenses 331.9   344.6 Insurance reserves 229.5   247.1 Net operating loss carryforwards 9.2   18.1 Bad debt reserves 119.6   154.8 State income tax 59.8   43.4 Deferred compensation 38.2   40.1 Investment basis difference 42.4   62.2 Other 110.5   68.4 Total deferred tax assets 1,304.0   1,343.5 Deferred tax liabilities relating to:       Unrealized gains on securities 202.9   127.8 Intangible assets:       Trademarks and state Medicaid licenses 2,547.6   2,547.6 Customer, provider and hospital relationships 194.1   269.2 Internally developed software and other amortization differences 450.5   436.6 Retirement benefits 267.3   252.7 Debt discount 60.8   61.9 State deferred tax 106.0   36.4 Depreciation and amortization 54.1   44.2 Other 200.6   197.7 Total deferred tax liabilities 4,083.9   3,974.1 Net deferred tax liability $ (2,779.9 )   $ (2,630.6 )
Components Of Provision For Income Taxes	Significant components of the provision for income taxes for the years ended December 31 consist of the following:   2016   2015   2014 Current tax expense:           Federal $ 1,862.6   $ 1,996.6   $ 1,629.4 State and local 93.9   133.0   65.8 Total current tax expense 1,956.5   2,129.6   1,695.2 Deferred tax expense (benefit) 129.1   (58.6 )   112.8 Total income tax expense $ 2,085.6   $ 2,071.0   $ 1,808.0
Reconciliation Of Income Tax Expense Computed At The Statutory Federal Income Tax Rate	A reconciliation of income tax expense recorded in the consolidated statements of income and amounts computed at the statutory federal income tax rate for the years ended December 31 is as follows:   2016   2015   2014   Amount   Percent   Amount   Percent   Amount   Percent Amount at statutory rate $ 1,594.4   35.0  %   $ 1,620.9   35.0  %   $ 1,528.8   35.0  % State and local income taxes net of federal tax benefit 61.5   1.4   75.3   1.6   49.0   1.1 Tax exempt interest and dividends received deduction (61.7 )   (1.4 )   (63.2 )   (1.3 )   (65.9 )   (1.5 ) HIP Fee 411.7   9.0   422.6   9.1   312.6   7.2 Other, net 79.7   1.8   15.4   0.3   (16.5 )   (0.4 ) Total income tax expense $ 2,085.6   45.8  %   $ 2,071.0   44.7  %   $ 1,808.0   41.4  %
Change In The Carrying Amount Of Gross Unrecognized Tax Benefits From Uncertain Tax Positions	The change in the carrying amount of gross unrecognized tax benefits from uncertain tax positions for the years ended December 31 is as follows:   2016   2015 Balance at January 1 $ 212.0   $ 115.8 Additions based on:       Tax positions related to current year —   39.8 Tax positions related to prior years 13.9   65.1 Reductions based on:       Tax positions related to current year (1.1 )   — Tax positions related to prior years (88.4 )   (7.9 ) Settlements with taxing authorities (5.3 )   (0.8 ) Balance at December 31 $ 131.1   $ 212.0