Debt (Carrying Value Of Long-Term Debt) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Oct. 09, 2012
Debt Instrument [Line Items]
Long-term debt	$ 15,286.9	$ 15,324.5
Current portion of long-term debt	(928.4)	0.0
Long-term debt, less current portion	14,358.5	15,324.5
Senior Unsecured Notes [Member] \| 2.375%, due 2017 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 400.1	$ 399.9
Interest rate on long-term debt	2.375%	2.375%
Senior Unsecured Notes [Member] \| 5.875%, due 2017 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 528.3	$ 527.6
Interest rate on long-term debt	5.875%	5.875%
Senior Unsecured Notes [Member] \| 1.875%, due 2018 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 624.3	$ 621.9
Interest rate on long-term debt	1.875%	1.875%
Senior Unsecured Notes [Member] \| 2.300%, due 2018 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 647.5	$ 645.9
Interest rate on long-term debt	2.30%	2.30%
Senior Unsecured Notes [Member] \| 2.250%, due 2019 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 845.6	$ 843.9
Interest rate on long-term debt	2.25%	2.25%
Senior Unsecured Notes [Member] \| 7.000%, due 2019 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 439.4	$ 438.9
Interest rate on long-term debt	7.00%	7.00%
Senior Unsecured Notes [Member] \| 4.350%, due 2020 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 700.0	$ 702.9
Interest rate on long-term debt	4.35%	4.35%
Senior Unsecured Notes [Member] \| 3.700%, due 2021 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 696.9	$ 696.2
Interest rate on long-term debt	3.70%	3.70%
Senior Unsecured Notes [Member] \| 3.125%, due 2022 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 843.8	$ 842.7
Interest rate on long-term debt	3.125%	3.125%
Senior Unsecured Notes [Member] \| 3.300%, due 2023 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 993.3	$ 992.2
Interest rate on long-term debt	3.30%	3.30%
Senior Unsecured Notes [Member] \| 3.500%, due 2024 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 791.9	$ 790.9
Interest rate on long-term debt	3.50%	3.50%
Senior Unsecured Notes [Member] \| 5.950%, due 2034 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 444.7	$ 444.5
Interest rate on long-term debt	5.95%	5.95%
Senior Unsecured Notes [Member] \| 5.850%, due 2036 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 768.3	$ 768.0
Interest rate on long-term debt	5.85%	5.85%
Senior Unsecured Notes [Member] \| 6.375%, due 2037 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 639.9	$ 639.6
Interest rate on long-term debt	6.375%	6.375%
Senior Unsecured Notes [Member] \| 5.800%, due 2040 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 193.9	$ 193.8
Interest rate on long-term debt	5.80%	5.80%
Senior Unsecured Notes [Member] \| 4.625%, due 2042 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 886.3	$ 885.8
Interest rate on long-term debt	4.625%	4.625%
Senior Unsecured Notes [Member] \| 4.650%, due 2043 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 985.9	$ 985.5
Interest rate on long-term debt	4.65%	4.65%
Senior Unsecured Notes [Member] \| 4.650%, due 2044 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 790.8	$ 790.5
Interest rate on long-term debt	4.65%	4.65%
Senior Unsecured Notes [Member] \| 5.100%, due 2044 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 593.6	$ 593.3
Interest rate on long-term debt	5.10%	5.10%
Senior Unsecured Notes [Member] \| 4.850%, due 2054 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 246.8	$ 246.6
Interest rate on long-term debt	4.85%	4.85%
Remarketable Subordinated Notes [Member] \| 1.900%, Due 2028 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 1,237.6	$ 1,236.1
Interest rate on long-term debt	1.90%	1.90%
Senior Convertible Debentures [Member] \| 2.750%, due 2042 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 334.1	$ 330.7
Interest rate on long-term debt	2.75%	2.75%	2.75%
Surplus Notes [Member] \| 9.000%, due 2027 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 24.9	$ 24.9
Interest rate on long-term debt	9.00%	9.00%
Commercial Paper [Member]
Debt Instrument [Line Items]
Commercial paper	$ 629.0	$ 682.2

Carrying value as of the balance sheet date of short-term borrowings using unsecured obligations issued by banks, corporations and other borrowers to investors. The maturities of these money market securities generally do not exceed 270 days.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(a)(3))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.13(2))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 16
-Article 7

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Carrying amount of long-term debt, net of unamortized discount or premium, including current and noncurrent amounts. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.16)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.16)
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 20, 22
-Article 5

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Carrying amount of long-term debt, net of unamortized discount or premium, excluding amounts to be repaid within one year or the normal operating cycle, if longer (current maturities). Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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